Remove PREVIOUS_BACKUP requirement when creating incremental server-side repository backups
Proposal
Incremental backups require that PREVIOUS_BACKUP
be specified. This backup tar is then extracted into the backup staging area. This is because incremental backups need access to the previous backup in order to determine what to include in the increment. Since server-side repository backups determine this directly from object storage, there is no need to either have access to or extract the previous backup tar.