[CI] Add a new action to check for stale PRs

[the-praxs]

📥 [CI] Add a new action to check for stale PRs

PR actions

1. PR is marked with the stale label if no commits are made in 14 days.
2. PR is closed 7 days after being marked stale.
3. When the PR is labelled stale an appropriate comment is added to the PR by tagging the author.
4. When the PR is closed the comment is added to the PR that its closed and can be reopened if required.
5. If there is a commit from anyone in the PR the CI removes the stale label and resets the timer of the days until it's marked stale.
6. No other labels are removed by the CI action so that we can search for them easily.

[gitguardian]

️✅ There are no secrets present in this pull request anymore.

If these secrets were true positive and are still valid, we highly recommend you to revoke them.
Once a secret has been leaked into a git repository, you should consider it compromised, even if it was deleted immediately.
Find here more information about risks.

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