Integrate arma-manager module

Dahlgren implemented functionality that allowed easy starting of an arma 3 server (https://github.com/Dahlgren/node-arma-server). He doesn't necessarily allows stopping it, but it is supposed to return the PID of the executable! We can use that to stop and check if the process is running.
Otherwise, checking the port listener and then grabbing the PID related there is another option.

Controls to implement:
- [x] start
- [x] stop
- [ ] status
- [ ] restart - Is there a way we can send chat commands to the server? Then we could imitate `#restart`
- [ ] update - Updates the game and any mods that are out of date. Use the FASTER XML to check on if anything is out of date? Might not work since FASTER is not guaranteed to be open or have checked for out-of-date mods in a while
- [ ] attendance - List the players who attended for the last event. An event is described as any session where the players were connected at any point during the 1900-2100 time period on a Wednesday, Thursday or Sunday
- ~~add_mod - Adds a mod to the start parameters of a particular server~~
- ~~remove_mod - Removes a mod from the start parameters of a particular server~~
- ~~add_server_mod~~
- ~~remove_server_mod~~