Cron script cleaning up the time-based apt-snapshots tmp dir

Following from https://labs.riseup.net/code/issues/13526 ,
the cron script added in:

https://git-tails.immerda.ch/puppet-tails/commit/?h=bugfix/13526-cleanup-apt-snapshots-tmpdir&id=5673109364ad0f973b01598be7e14748270b3f7e

should help with garbage collection and maintaining enough free space.

Feature Branch: immerda/puppet-tails:bugfix/13526-cleanup-apt-snapshots-tmpdir

Related issues

• Related to #13526 (closed)
• Blocks #13233 (closed)

Original created by @groente on 13579 (Redmine)