Add RTV check / Do some cleanup

This adds test kitchen support, and some misc cleanup. But the ultimate goal is to add a check for rock the vote (which isn't included in this PR yet).
Installation of the client package requires a [node search](https://github.com/osuosl-cookbooks/nagios/blob/master/recipes/client.rb#L29-46) of the nagios server. I'm not sure how to work around this without changing the nagios cookbook.