[chore] add codeowner activity report workflow (#46015)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

This PR adds a workflow that reports code-owners' activity. The workflow
only focuses on components that are listed for stability at
#44130
since that's the main priority for now. We can expand the report for all
components in contrib but that might be a bit noisy.

Similar work is done in other SIGs, i.e
open-telemetry/opentelemetry-js#5898

<!-- Issue number (e.g. #1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Related to
open-telemetry/opentelemetry-collector#14107

<!--Describe what testing was performed and which tests were added.-->
#### Testing

Running locally with:

```console
export DRY_RUN=1
export GITHUB_TOKEN=ghp_foobarzet
node -e "
const { Octokit } = require('@octokit/rest');
const script = require('./.github/workflows/scripts/generate-codeowners-activity.js');
const octokit = new Octokit({ auth: process.env.GITHUB_TOKEN });
script({
  github: { rest: octokit },
  context: { payload: { repository: { owner: { login: 'open-telemetry' } } } }
});
"
```

<!--Describe the documentation added.-->
#### Documentation
~
<!--Please delete paragraphs that you did not use before submitting.-->

#### AI Usage disclaimer

**_The script of this PR is crafted mainly by using Cursor_** taking
inspiration from the Weekly Report workflow script:
[/.github/workflows/scripts/generate-weekly-report.js](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/d0cd8a546f274e3aadbc43cf5cb5d693633365e4/.github/workflows/scripts/generate-weekly-report.js#L4)

---------

Signed-off-by: ChrsMark <chrismarkou92@gmail.com>
Co-authored-by: Pablo Baeyens <pbaeyens31+github@gmail.com>
Co-authored-by: Andrzej Stencel <andrzej.stencel@elastic.co>

Author: 3 people

.github/workflows/generate-codeowners-activity.yml

@@ -0,0 +1,42 @@
+# This workflow generates a code owner activity report as a GitHub issue.
+# It measures whether code owners have reviewed/replied to
+# PRs opened against each component (by component label).
+# We target at least 75% of each component's PRs to be reviewed by a code owner,
+# and each code owner to respond to at least 75% / n of their requested PRs (n = number of code owners for that component)
+# (at least 3 code owners are required for components aiming for stable).
+
+name: 'Generate Code Owner Activity Report'
+on:
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: 'Dry run (print report only, do not create issue)'
+        required: false
+        default: false
+        type: boolean
+  schedule:
+    # run on the 1st of every month at 2am UTC
+    - cron: "0 2 1 * *"
+
+permissions:
+  contents: read
+
+jobs:
+  report:
+    permissions:
+      contents: read
+      issues: write
+      pull-requests: read
+    runs-on: ubuntu-24.04
+    if: ${{ github.repository_owner == 'open-telemetry' }}
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      - uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
+        id: report
+        env:
+          DRY_RUN: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.dry_run == 'true' && 'true' || '0' }}
+        with:
+          retries: 3
+          script: |
+            const script = require('.github/workflows/scripts/generate-codeowners-activity.js')
+            await script({github, context})