ci: add stale issue handler action

[jssotomdz]

Quick draft on how the action could look like.
Found this suggestion about marking them as stale if open without any activity for 30 days and closing in another 30 days. This way we could "warn" both the opener and us to reply in case something is stuck and they/we have new info to discuss.

Also, Tim talked about the possibility of not affecting existing issues. Is that something I should include in this draft?

[ashuntu]

My personal opinion is that it would probably be a good idea to start this from now on, and not be retroactive. The reason being that old issues haven't been "maintained" to the new standard that we are targeting, so it's not entirely fair to close them automatically. We should go through old issues manually and make sure they're actually stale.

I also still don't feel amazing about closing issues that aren't actually resolved (labels are fine), but that's for later discussion perhaps. Maybe we need a label that we can add to forcibly keep issues open?

[jssotomdz]

Ok, added the start date parameter as today commented out. When we agree on the rest of the stuff (in case we still need to discuss something), I'll update it with that day's date, uncomment and remove the draft from the PR

[tim-hm]

I agree with @ashuntu in that we should apply this going forward and not retroactively. I also agree that we need to keep discussing how to manage issues that don't have a clear resolution ... I would love for there to be a clear path for how we should approach them. Maybe if we had a tag, that when applied, the issue becomes excempt? Additionally, we should ask for community feedback.

One nit bit on the commit message. Typically you want to limit the subject line to 50 characters and the body to 72 characters as this ensures wide reability. For example the current subject is truncated:

How about something like: ci: add stale issue handler action