Option to remove label when there are no issues using it (for some time)
Description
We use labels to group issues, including planning issues for specific sprint. After the sprint is over, the label is not needed anymore, but "by default" stays with the issue and this over time can produce a lot of labels that do not make any sense (anymore).
Proposal
Define label cleanup rules. One possible solution might be defining X days, after which label will be "archived" or deleted in case it does not have any open issues associated (so X days after closing the last labeled issue).
This might obviously also apply to scenario when label is not used at all - although it is not my use case.
Links / references
NOTE: this is different from !13874 (closed) because i don't necessarily want to remove the labels (this might be fine in some cases, but will "lose" some historical information in others, which i dont want).
Instead, it is about "archiving" items away from labels list.