Add stalebot

[frenck]

This PR adds stalebot to this repository:

• Only handles issues, PR's are untouched
• Doesn't touch issues in a milestone
• Doesn't touch issues on a project board
• Doesn't touch issues with tag:
  • feature request
  • Help wanted
  • to do
• 90 days until first notification
• 7 days after first notification without response closes the issue

[iantrich]

I have a feeling I'm going to have to remove stale labels a lot with this. We don't have enough devs to work through the backlog, doesn't mean the issues aren't valid/workable.

[frenck]

Not enough devs on the backlog also cause the backlog to grow with things that aren't relevant anymore cluttering our view.

The first run will not be pretty, although it limits itself to a number max issues per run.

Feature requests are left alone, so that is not lost. This is mere to get the bug reports cleaned up over time AND find issues that aren't tagged properly.

[bramkragten]

I think it will also save a lot of work going through issues that are no longer a problem.

[iantrich]

fair enough 🚀