More advanced archiving

[OmerSabic]

Description of the feature
I would like for a way to archive every x backup but remove the rest. So for example, if I'm doing daily backups and keeping the latest week of backups in the folder. I would like to archive every 7th backup. The rest will be deleted as normal.

Benefits of feature
This would help keep recent backups and long-term backups at the same time without taking up too much space. We find it very useful for our support team to have backups of the last few days. We also need long-term backups in the case something goes wrong. But keeping a backup of every day would require a lot of storage. This feature would allow for us to have the best of both worlds.