Add hidden_services and exclude them from c-s-c status calls.

Add concept of `hidden_services` that don't show up in `chef-server-ctl status`.

Ping @opscode/server-team 
I'm just being consistent with what is there. Constants would be better, but we'd wanna refactor out all the strings being used in this manner in that case (not a bad idea, just not in the scope of what I was doing).