backend: Run aptly cleanup script on a weekly basis
This aptly script performs a database cleanup to remove information about unreferenced packages. Also deletes files in the package pool that aren't used by packages anymore. Aptly documentation suggests that it's a good idea to run this command after massive deletion of mirrors, snapshots or local repos. This commit adds the script to be called in a weekly basis by cron. Note that with this configuration it will be called each Sunday at 00:00 hours. Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>