add Unixlistener

[LuckyTurtleDev]

replace: #51
fix: #49

Change config:
move port and listen to a single new listener .
If listener start with with the prefix unix://, the listener will be interpreted as unix listener.

[LuckyTurtleDev]

i am not sure if i want to delete random files at start. It would be probably be better to just delete the socket at the drop implementation.

[msrd0]

No, you should not delete the socket file if it exists. Some daemon orchestrators like systemd will actually create the socket themselves and expect you to use that socket. I believe they also have a mode where they listen on the socket, and if a request comes in, starts the service on demand. But I have never used that feature of systemd, so I wouldn't know for sure, but I believe I read that systemd sets an environment variable so you'd know to re-use that socket, but then again I am against systemd-specific solutions, so I think we should just re-use the existing socket whenever we can.

Also, it should be possible to set user/group/permissions on the unix socket file. Especially when the socket was not created by systemd, this comes in handy. But this can be done in a follow-up PR.