Clear out old Mastodon backups

[AetherUnbound]

@mpuckett159 graciously set up hourly backups on our Mastodon server. These backups are being retained indefinitely and they do not need to be.

From her:

Can we set up moderately complicated logic like hourlies for a day, dailies for a week, weeklies for a month, no more after a month?

I think our best bet is to list all the backups, determine which ones to delete in Python, then issue those delete commands over SSH (rather than trying to do this all in bash). That way we could also write unit tests too 😄

Paired with a DAG which may also cover https://github.com/OrcaCollective/orca-collective-terraform/issues/12, this would help reduce disk space.

[AetherUnbound]

I misunderstood this, I don't think the backups themselves actually exist on the server, but rather in our Digital Ocean Space. We'll just need to iterate through that and clear them out.