[CHORE] Automate stale-issue detection and closure where appropriate

[cupofcat]

We should build some automation to mark issues as stale, ping users, and perhaps auto-close things.

I think we can (and should) do this on the org-level with a solution like this: actions/stale#1089 (reply in thread), however, I would advocate we should just host this code ourselves in the community-tooling repo, since this involves the use of a custom fork of another popular action.