The old code was wrong because e.g. systemd can be *installed* on the
system, but not actually used as PID1. In that case we would pick
`systemctl`, but it wouldn't actually work because PID1 was some other
init system.
Should solve the occasional bugs with the restart in the WebUI.
Sometimes the service stops and then doesn't start again; this will run
an explicit start action afterwards. If this doesn't fix it I'm certain
there would be more tweaking that can be done.
