docs: Fix all credential documentation urls, and add a CI job to regularly validate these urls (#5012)

* add or update documentation URLs for all credentials

* add UTM params to documentation urls even when they are absolute urls

* Setup a CI job to validate documentation urls after every release

* Fix FacebookGraphApi documentation URL

* also validate node documentation urls

Co-authored-by: Jan Oberhauser <jan.oberhauser@gmail.com>

.github/workflows/check-documentation-urls.yml

@@ -0,0 +1,41 @@
+name: Check Documentation URLs
+
+on:
+  push:
+    tags:
+      - n8n@*
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    timeout-minutes: 5
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: pnpm/action-setup@v2.2.4
+
+      - uses: actions/setup-node@v3
+        with:
+          node-version: 16.x
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Build nodes-base
+        run: pnpm --filter n8n-workflow --filter=n8n-core --filter=n8n-nodes-base build
+
+      - name: Test URLS
+        run: node scripts/validate-docs-links.js
+
+      - name: Notify Slack on failure
+        uses: act10ns/slack@v2.0.0
+        if: failure()
+        with:
+          status: ${{ job.status }}
+          channel: '#updates-build-alerts'
+          webhook-url: ${{ secrets.SLACK_WEBHOOK_URL }}
+          message: Documentation URLs check failed (${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})