[Feature Request] Provide a way of creating a user level systemd service for PulseAudio mode

[GioF71]

Is your feature request related to a problem? Please describe.
If we want an automatically starting container configured in PulseAudio mode on a desktop system, we probably cannot use a restart policy from docker, which seems to break PulseAudio (at least on my systems)

Describe the solution you'd like
As done with squeezelite-docker, a user level systemd service would solve the issue.

Describe alternatives you've considered
No alternatives that I know of, that do not require a manual interaction (like, e.g., starting an existing container from the command line or from Poirtainer)

Additional context
This applies to PulseAudio mode so basically to system with a desktop environment without auto-login. Automati login might probably mitigate the issue

[GioF71]

Release in 2022-10-08