Add Stale Issue / PR GitHub Action (#1617)

- Starting with high values because we have not had this before
- Initial values should be 300 days => stale and 30 days => close

.github/workflows/stale.yml

@@ -0,0 +1,26 @@
+name: 'Stale issue handler'
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 7 * * *'
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v4.0.0
+        id: stale
+        with:
+          stale-issue-message: 'This Issue will be closed in 30 days. Please remove the "Stale" label or comment to avoid closure with no action.'
+          stale-pr-message: 'This PR will be closed in 30 days. Please remove the "Stale" label or comment to avoid closure with no action.'
+          days-before-stale: 300
+          days-before-close: 30
+          stale-issue-label: 'stale'
+          stale-pr-label: 'stale'
+          close-issue-label: 'closed'
+          close-pr-label: 'closed'
+          exempt-issue-labels: 'bug,enhancement,documentation,waiting,keep'
+          exempt-all-milestones: true
+          exempt-all-assignees: true
+      - name: Print outputs
+        run: echo ${{ join(steps.stale.outputs.*, ',') }}