ci: Automatically label and close stale issues

[LukasWoodtli]

This helps to keep the list of issues short and relevant.

Should we do some automatic clean-up tasks?

If yes: Should we also automatically close old PRs?

TODO: remove debug-only

[sbernard31]

First, you are the most active committer on this project, so if you think it's a good idea, feel free to add this.

My 2 cts :

• I'm not sure why an inactive old issue should be closed. I mean if there is an issue like "feature request", I'm not sure that inactivity is good reason to close it. FMPOV a good reason should be : "implemented", "out of scope", ...
• If feature is in the scope but not the priority of the team it's fine to keep it open for a long time.
• Maybe it makes more sense for PR but I still prefer issue/PR was closed manually with a real reason. From a contributor perspective, this is a bit frustrating to see an issue closed "automatically because inactivity".
• I feel that for now there is no so much issue open by week and so this should be manageable manually.
• For the current 74 issue and 14 PR opened, there is maybe very old issue which should be closed. So maybe it would be worth it to check it one by one and see if some of them should be closed or not. It's totally fine for some of them to put a message like "This issue was created before the revival of Wakaama 📢 Wakaama Revival ! 🏗 #488 and I'm not sure this issue/PR is still relevant because code base changed a lot, I close it but feel free to comment/reopen if this is still needed" (or something better but you see the idea 🙂 )

But again, If you prefer the automatic job, feel free to do that.