Define consul::service and consul::check types

Corresponding to [services](http://www.consul.io/docs/agent/services.html) and [checks](http://www.consul.io/docs/agent/checks.html).

I renamed `class consul::service` to `class consul::run_service`, because I wanted the `consul::service` name for this resource type (anything else would be clunky). I'm open to suggestions about what the name of the `consul::run_service` class should be.