Dorian/checkprocess

Add service check for the process check.
I don' t think this message is particularly useful. It might be nice to show something similar to what nagios would show with `check_proc`. Here's an example from the nagios output: `PROCS OK: 3 processes with UID = 106 (dd-agent), args 'agent'`.

We don't have to copy that exactly but it should say something about the number of processes matching.