docs: add GitLab Runner integration documentation

  Add comprehensive documentation for GitLab Runner integration feature,
  covering prerequisites, token creation (project and personal access
  tokens), and usage examples for AWS and Azure providers.

Signed-off-by: Jose Angel Morena <jmorenas@redhat.com>

Author: jangel97

README.md

@@ -31,5 +31,6 @@ Currently each target offered by Mapt can be added as:
 
 * [Github Self Hosted Runner](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners/about-self-hosted-runners)
 * [Cirrus Persistent Worker](https://cirrus-ci.org/guide/persistent-workers/)
+* [GitLab Runner](docs/gitlab-runner.md)
 
 And [Tekton taks](tkn) are offered to dynamically provision the remote target to use within tekton pipelines

docs/gitlab-runner.md

@@ -0,0 +1,91 @@
+# Overview
+
+This feature of `mapt` allows you to set up hosts deployed by it as GitLab Runners, which can then be directly used for running GitLab CI/CD jobs.
+It benefits from all the existing features that `mapt` already provides, allowing you to create self-hosted runners that can be used for different QE scenarios.
+
+## Providers and Platforms
+
+Currently, it allows you to create self-hosted GitLab runners on AWS (Fedora, RHEL, Windows Server, macOS) and Azure (RHEL, Windows Desktop).
+
+### Prerequisite
+
+To register a GitLab Runner, you need an access token with `create_runner` and `manage_runner` scopes. There are two options:
+
+#### Option 1: Project Access Token (Recommended)
+
+Project Access Tokens are scoped to a specific project, making them more secure than personal tokens.
+
+**Requirements:**
+* GitLab Premium/Ultimate (on GitLab.com)
+* OR self-managed GitLab instance (version 13+)
+
+**Steps:**
+1. Go to your project → **Settings** → **Access Tokens**
+2. Create a new token with:
+   - **Token name**: `mapt-runner`
+   - **Role**: `Maintainer` or `Owner`
+   - **Scopes**: Select `create_runner` and `manage_runner`
+   - **Expiration**: Set according to your needs
+3. Click **Create project access token**
+4. Copy the token immediately
+
+#### Option 2: Personal Access Token (Fallback)
+
+If Project Access Tokens are not available, use a Personal Access Token:
+
+1. Go to **User Settings** → **Access Tokens**
+2. Create a new token with:
+   - **Token name**: `mapt-runner-token`
+   - **Scopes**: Select `create_runner` and `manage_runner`
+   - **Expiration**: Set according to your needs
+3. Click **Create personal access token**
+4. Copy the token immediately
+
+#### Getting Project or Group ID
+
+You also need either a Project ID or Group ID:
+
+* **Project ID**: Go to your project → **Settings** → **General** (displayed at the top)
+* **Group ID**: Go to your group → **Settings** → **General** (displayed at the top)
+
+> *NOTE:* For Group Runners with Group Access Tokens, you'll need GitLab Premium/Ultimate on GitLab.com or a self-managed instance.
+
+### Operations
+
+After obtaining the token and the project/group ID, you can deploy a runner using the appropriate flags.
+
+**Required flags:**
+* `--glrunner-token` - Your GitLab access token (project or personal)
+* `--glrunner-url` - GitLab instance URL (e.g., `https://gitlab.com`)
+* `--glrunner-project-id` OR `--glrunner-group-id` - Either project or group ID (not both)
+
+**Optional flags:**
+* `--glrunner-tags` - Comma-separated tags (e.g., `aws,mapt,fedora`)
+
+To deploy a Fedora runner on AWS as a project runner:
+
+```bash
+mapt aws fedora create --spot \
+    --glrunner-token="glpat-xxxxxxxxxxxxxxxxxxxx" \
+    --glrunner-url="https://gitlab.com" \
+    --glrunner-project-id="12345678" \
+    --glrunner-tags="aws,fedora,mapt" \
+    --project-name mapt-fedora-aws \
+    --backed-url file:///Users/tester/workspace \
+    --conn-details-output /Users/tester/workspace/conn-details
+```
+
+To deploy a RHEL runner on Azure as a group runner:
+
+```bash
+mapt azure rhel create --spot \
+    --glrunner-token="glpat-xxxxxxxxxxxxxxxxxxxx" \
+    --glrunner-url="https://gitlab.com" \
+    --glrunner-group-id="87654321" \
+    --glrunner-tags="azure,rhel,mapt" \
+    --project-name mapt-rhel-azure \
+    --backed-url file:///Users/tester/workspace \
+    --conn-details-output /Users/tester/workspace/conn-details
+```
+
+> *NOTE:* If no tags are provided with `--glrunner-tags`, the runner can run untagged jobs. If tags are provided, the runner only runs jobs matching those tags.