[feature] add deduplication, pruning, etc to `etcd` backups

[judahrand]

Problem Description

Sometimes cluster state does not change for an extended period. It is wasteful in these cases to store an entire snapshot of etcd in object storage for every backup. Additionally, given that there is no removal mechanism the amount of storage used is unbounded.

Solution

Use a proper backup tool like restic to handle the backups. This would add deduplication, pruning, expiry etc to the backups.

Alternative Solutions

No response

Notes

No response