Backup refactor.

- Change from a single backup that's overwritten everytime to a
  multiple, dated backups.
- Save the last 30 days of backups.
- Save backups under the host's /var/backups instead of a Docker volume.
  Easier to backup.
- Add a restore script so that at least I would have some idea on how to
  restore this backup. Last thing I want to do when I need this backup
is to try and figure out how to restore it.