Add stale action to close older issues/PR that are more than one year inactive (facebook#32403)

Summary:
Pull Request resolved: facebook#32403

As the title says, we should cleanup issues that are really stale (i.e. more than one year inactive).
I ended up using actions/stale which is the first party solution for this.

Changelog:
[Internal] [Changed] - Add stale GitHub action

Reviewed By: hramos

Differential Revision: D31653083

fbshipit-source-id: 48538a571183f9ff28a23e7d1fdd01980581de35

Author: cortinico

.github/workflows/stale-bot.yml

@@ -0,0 +1,19 @@
+name: Mark stale issues and pull requests
+on:
+  schedule:
+    - cron: "30 1 * * *"
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - uses: actions/stale@v4
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          days-before-stale: 365
+          stale-issue-message: 'This issue is stale because it has been open 365 days with no activity. Remove stale label or comment or this will be closed in 7 days.'
+          stale-pr-message: 'This PR is stale because it has been open 365 days with no activity. Remove stale label or comment or this will be closed in 7 days.'
+          close-issue-message: 'This issue was closed because it has been stalled for 7 days with no activity.'
+          close-pr-message: 'This PR was closed because it has been stalled for 7 days with no activity.'