### Description
This ensures that when the LibreTime interface is not used for a long
time, we still have the task manager run essential tasks for the
schedule.
Related to #2670
BREAKING CHANGE: The worker `RMQ_CONFIG_FILE` environement variable has
been renamed to `LIBRETIME_CONFIG_FILEPATH`. In addition the systemd
working directory for the worker has changed from `/srv/airtime` to
`/var/lib/libretime/worker`.