Allow unit file customization

This will allow merging the module without it restarting all docker services

What's Changed

• Allow unit file configuration by @jplana-tef in #2

New Contributors

• @jplana-tef made their first contribution in #2

Full Changelog: v5.3.1-tuenti5...v5.3.1-tuenti6

Remove systemd service when setting ensure => absent on a run instance

v5.3.1-tuenti3

Remove systemd service unit when setting ensure => absent