Enabling Github stale bot

[mattdibi]

Hello everyone 👋 ,

with #4910 we plan to enable the Github Stale bot to avoid Issues/Pull Request pile-up in the Eclipse Kura repo. As documented in the CONTRIBUTING.md file the bot will:

• Automatically tag an Issue/Pull Request as "stale" after 60 days of inactivity (i.e. no comments/commits etc.)
• Automatically close an Issue/Pull Request after being "stale" for 14 days without any update

In exceptional cases we can add the exempt-stale label to let an Issue/Pull Request be ignored by the workflow (e.g. for long standing issues, changes that require a major release and thus need to wait for that etc.)

Feel free to use this Github Discussion to raise your concerns about this change of policy or providing feedback. In absence of those we'll merge #4910 at the end of this week.

[mattdibi]

#4910 was merged and the bot enabled