Add systemd service on ARM builds

Raspbian uses systemd. Unfortunately the ARM build for the deb package doesn't provide them. It's very useful though for auto start after network is on.

I haven't tested the code.

changed milestone to %2.0

@Tuxicoman est-ce toujours d'actualité ? Si oui il faut tester, une contribution non testée ne peut hélas pas être mergée :)

added S-waiting author label

closed