Copy over stalebot config from core repo

web/.github/stale.yml

@@ -0,0 +1,27 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 60
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 7
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - backlog
+# Label to use when marking an issue as stale
+staleLabel: stale
+# Comment to post when marking an issue as stale. Set to `false` to disable
+markComment: >
+  This issue has been automatically marked as stale because it has not had
+  recent activity. It will be closed if no further activity occurs. Thank you
+  for your contributions.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: false
+exemptMilestones: true
+
+# Since old PRs are less useful than old issues ping them sooner.
+pulls:
+  daysUntilStale: 30
+  markComment: >
+    This pull request has not had any activity in 30 days. Since things move fast it's best 
+    to get PRs merged in, or to allow somebody else to work on it so the change can get in.
+    This PR will be closed if no further activity occurs. Thank you for your contributions!
+  exemptLabels:
+      - bot