this is useful for clone also to copy notes, operators, checklist
of the time when the backup was made (as opposed to current)
at this point, it's not clear why we need a archives table. it's
an optimization to not have to store icon for every backup.
Cleaner to separate things from the backups table.
* icon, appConfig, appStoreIcon etc are only valid for archives
* older version cloudron does not have appConfig in backups table (so it
cannot be an archive entry)
