Gitlab data source connector

[Apmats]

Closes https://github.com/elastic/search-team/issues/11093

This PR includes a new data source / connector for Gitlab - mainly fetching project management related entities.
We fetch and generate docs for:

Projects - Repository metadata (name, description, visibility, stars, forks, etc.)
Issues - Project issues with full metadata (assignees, labels, comments, status)
Epics - Group-level epics for tracking larger initiatives (Premium/Ultimate tier)
Merge Requests - Code review requests with discussions, approvals, and reviewers
Releases - Version releases with changelogs, milestones, and asset links
Files - README files (.md, .rst, .txt) from project repositories

Currently this is yielding docs like this:

Epic:
--------------------------------------------------------------------------------
{
  "_id": "epic_testapmats_1",
  "_timestamp": "2025-10-08T13:01:19Z",
  "type": "Epic",
  "group_id": "testapmats",
  "group_path": "testapmats",
  "iid": 1,
  "title": "Nulla tempore voluptatibus error.",
  "description": "### Voluptate\nQui quaerat praesentium. Voluptates temporibus quae. Libero aliquid quod. Nihil rerum earum. Inventore et illum.\n`Quod.`",
  "state": "OPEN",
  "created_at": "2025-10-08T05:25:54Z",
  "updated_at": "2025-10-08T13:01:19Z",
  "closed_at": null,
  "web_url": "https://gitlab.com/groups/testapmats/-/epics/1",
  "author": "apmats",
  "author_name": "Apostolos Matsagkas",
  "assignees": [
    "apmats"
  ],
  "labels": [],
  "children_count": 1,
  "children": [
    {
      "id": "gid://gitlab/WorkItem/174153667",
      "iid": 10,
      "title": "Id tempore minus molestiae."
    }
  ],
  "linked_items_count": 1,
  "linked_items": [
    {
      "link_id": "gid://gitlab/WorkItems::RelatedWorkItemLink/7148349",
      "link_type": "relates_to",
      "link_created_at": "2025-10-08T13:00:55Z",
      "link_updated_at": "2025-10-08T13:00:55Z",
      "work_item_id": "gid://gitlab/WorkItem/174154216",
      "work_item_iid": 28,
      "work_item_title": "Ut quae nesciunt facere."
    }
  ],
  "notes": [
    {
      "id": "gid://gitlab/DiscussionNote/2805807667",
      "body": "### Voluptatem\nQuae sint porro. Error id ut. Molestiae nisi iusto. Mollitia iste saepe. Dolor delectus soluta.\n* Voluptatem. \n* Unde. \n* Deserunt. \n* Sunt. \n* Vel.\n\n *By Administrator on 2021-02-15T15:56:33*",
      "created_at": "2021-02-15T15:56:33Z",
      "updated_at": "2021-02-15T15:56:33Z",
      "system": false,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    },
    {
      "id": "gid://gitlab/Note/2805807678",
      "body": "Hey",
      "created_at": "2025-10-06T08:19:32Z",
      "updated_at": "2025-10-06T08:19:32Z",
      "system": false,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    },
    {
      "id": "gid://gitlab/Note/2805807679",
      "body": "assigned to @apmats",
      "created_at": "2025-10-07T22:35:13Z",
      "updated_at": "2025-10-07T22:35:13Z",
      "system": true,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    }
  ]
}


File:
--------------------------------------------------------------------------------
{
  "_id": "file_74928810_README.md",
  "_timestamp": "2025-10-08T05:25:55Z",
  "type": "File",
  "project_id": 74928810,
  "project_path": "testapmats/connectortestproj",
  "file_path": "README.md",
  "file_name": "README.md",
  "extension": ".md",
  "web_url": "https://gitlab.com/testapmats/connectortestproj/-/blob/master/README.md"
}


Issue:
--------------------------------------------------------------------------------
{
  "_id": "issue_74928810_30",
  "_timestamp": "2025-10-08T05:25:55Z",
  "type": "Issue",
  "project_id": 74928810,
  "project_path": "testapmats/connectortestproj",
  "iid": 30,
  "title": "Nulla tempore voluptatibus error.",
  "description": "### Voluptate\nQui quaerat praesentium. Voluptates temporibus quae. Libero aliquid quod. Nihil rerum earum. Inventore et illum.\n`Quod.`",
  "state": "CLOSED",
  "created_at": "2021-02-15T15:56:04Z",
  "updated_at": "2025-10-08T05:25:55Z",
  "closed_at": "2025-10-08T05:25:55Z",
  "web_url": "https://gitlab.com/testapmats/connectortestproj/-/issues/30",
  "author": "apmats",
  "author_name": "Apostolos Matsagkas",
  "assignees": [
    "apmats"
  ],
  "labels": [
    "et-facere",
    "nisi-et",
    "suscipit-consectetur"
  ],
  "children_count": 0,
  "children": [],
  "linked_items_count": 0,
  "linked_items": [],
  "notes": [
    {
      "id": "gid://gitlab/LabelNote/0dad54c6400422b1e72e91ef6890651b1e2c74af",
      "body": "added ~42915054 ~42915032 ~42915100 labels",
      "created_at": "2021-02-15T15:56:04Z",
      "updated_at": "2021-02-15T15:56:04Z",
      "system": true,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    },
    {
      "id": "gid://gitlab/DiscussionNote/2788636988",
      "body": "### Voluptatem\nQuae sint porro. Error id ut. Molestiae nisi iusto. Mollitia iste saepe. Dolor delectus soluta.\n* Voluptatem. \n* Unde. \n* Deserunt. \n* Sunt. \n* Vel.\n\n *By Administrator on 2021-02-15T15:56:33*",
      "created_at": "2021-02-15T15:56:33Z",
      "updated_at": "2021-02-15T15:56:33Z",
      "system": false,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    },
    {
      "id": "gid://gitlab/Note/2800180491",
      "body": "Hey",
      "created_at": "2025-10-06T08:19:32Z",
      "updated_at": "2025-10-06T08:19:32Z",
      "system": false,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    }
  ]
}


Merge Request:
--------------------------------------------------------------------------------
{
  "_id": "mr_74928810_30",
  "_timestamp": "2025-10-06T13:53:21Z",
  "type": "Merge Request",
  "project_id": 74928810,
  "project_path": "testapmats/connectortestproj",
  "iid": 30,
  "title": "Id blanditiis consequatur ut.",
  "description": "##### Voluptatum\nPorro et quo. Laborum molestias ducimus. Labore dolorum adipisci. Quisquam est quis. Sint accusamus maxime.\n* Veritatis. \n* Eos. \n* Adipisci. \n* Quibusdam. \n* Sint. \n* Consequuntur. \n* Hic. \n* Voluptate. \n* Velit.",
  "state": "opened",
  "created_at": "2021-02-15T15:55:38Z",
  "updated_at": "2025-10-06T13:53:21Z",
  "merged_at": null,
  "closed_at": null,
  "web_url": "https://gitlab.com/testapmats/connectortestproj/-/merge_requests/30",
  "source_branch": "laudantium-unde-et-iste-et",
  "target_branch": "master",
  "author": "apmats",
  "author_name": "Apostolos Matsagkas",
  "assignees": [],
  "reviewers": [],
  "approved_by": [],
  "merged_by": null,
  "labels": [
    "asperiores-ex",
    "quidem-labore",
    "sed-consequuntur"
  ],
  "notes": [
    {
      "id": "gid://gitlab/Note/2788661393",
      "body": "###### Quos\nVero ipsam consequatur. Eum provident consequatur. Saepe aut mollitia. Sit possimus nihil. Aspernatur sed id.\n0. Aspernatur. \n1. Perspiciatis. \n2. Dolorem. \n3. Ut. \n4. Impedit. \n5. Esse. \n6. Ratione. \n7. Et. \n8. Repellendus. \n9. Laudantium.\n\n *By Administrator on 2021-02-15T15:55:59*",
      "created_at": "2021-02-15T15:55:59Z",
      "updated_at": "2021-02-15T15:55:59Z",
      "system": false,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas"
    },
    {
      "id": "gid://gitlab/DiffNote/2801394791",
      "body": "Test test test it's me!",
      "created_at": "2025-10-06T13:53:21Z",
      "updated_at": "2025-10-06T13:53:21Z",
      "system": false,
      "author": "apmats",
      "author_name": "Apostolos Matsagkas",
      "position": "new_line=2 old_line=None new_path='README.md' old_path='README.md' position_type='text'"
    }
  ]
}


Project:
--------------------------------------------------------------------------------
{
  "_id": "project_74928810",
  "_timestamp": "2025-10-08T05:25:55Z",
  "type": "Project",
  "id": 74928810,
  "name": "Connectortestproj",
  "path": "connectortestproj",
  "full_path": "testapmats/connectortestproj",
  "description": "",
  "visibility": "private",
  "star_count": 0,
  "forks_count": 0,
  "created_at": "2025-09-30T13:38:51Z",
  "last_activity_at": "2025-10-08T05:25:55Z",
  "archived": false,
  "default_branch": "master",
  "web_url": "https://gitlab.com/testapmats/connectortestproj"
}


Release:
--------------------------------------------------------------------------------
{
  "_id": "release_74928810_test-release-tag",
  "_timestamp": "2025-10-07T09:12:14Z",
  "type": "Release",
  "project_id": 74928810,
  "project_path": "testapmats/connectortestproj",
  "tag_name": "test-release-tag",
  "name": "Testrelease1",
  "description": "Test release notes",
  "created_at": "2025-10-07T09:12:14Z",
  "released_at": "2025-10-07T09:12:14Z",
  "author": "apmats",
  "author_name": "Apostolos Matsagkas",
  "milestones": [],
  "asset_count": 4,
  "commit_sha": "27329d3afac51fbf2762428e12f2635d1137c549",
  "commit_title": "Update README.md"
}

Still remaining

• Tests
• Kibana work
• Test account to be captured in connectors-infra (subscription required to have access to premium features like Epics)

Checklists

Pre-Review Checklist

• this PR does NOT contain credentials of any kind, such as API keys or username/passwords (double check config.yml.example)
• this PR has a meaningful title
• this PR links to all relevant github issues that it fixes or partially addresses
• if there is no GH issue, please create it. Each PR should have a link to an issue
• this PR has a thorough description
• Covered the changes with automated tests
• Tested the changes locally
• Added a label for each target release version (example: v7.13.2, v7.14.0, v8.0.0)
• For bugfixes: backport safely to all minor branches still receiving patch releases
• Considered corresponding documentation changes
• Contributed any configuration settings changes to the configuration reference
• if you added or changed Rich Configurable Fields for a Native Connector, you made a corresponding PR in Kibana

Changes Requiring Extra Attention

• Security-related changes (encryption, TLS, SSRF, etc)
• New external service dependencies added.

Related Pull Requests

Release Note

[Apmats]

This is to be deleted, just providing it for anyone doing an early review if they want to test how output looks, if pagination works etc.

[Apmats]

Using pydantic to parse responses from APIs - I think this dependency is worth picking up. Makes the code much more readable and we will get descriptive errors when things fail if the API changes, and the failure will be when we parse the response, not down the line in the code when we try to access an unstructured dictionary.