Make Mariabackup handle both --backup and --prepare in a single execution

After taking a full backup with Mariabackup, the backup currently needs to be prepared before it can be restored. e.g.:

$ mariabackup --backup \

   --target-dir=/var/mariadb/backup/ \

   --user=mariabackup --password=mypassword

$ mariabackup --prepare \

   --target-dir=/var/mariadb/backup

$ mariabackup --copy-back \

   --target-dir=/var/mariadb/backup/

https://mariadb.com/kb/en/library/full-backup-and-restore-with-mariabackup/

This can be confusing to users who migrate from other databases, where backups do not need to be manually "prepared" before they can be restored.

Would it be feasible for Mariabackup to prepare the full backup immediately after it has been taken, so that users do not need to manually prepare it?