Remove backups of deleted PVs

Following !1 (merged)

It is required to clarify when the PVs are going to be deleted, on the other hand, it is also required to prune the backups after a period, still needs to be clarified which value should we set for this.

Restic can't run in parallel so we have to implement some logic here to forget backups somehow. If this would be possible we could create an init container before any other job starts.

Implement the removal of the backups when the main PV is deleted and delete the backups after 30 days.