Feature/add configure recipe

Hey
i'm using the nrpe and it works great.

This PR adds a new recipe `configure` to be able to configure the nrpe service later on.
Currently my scenario is that i sometimes need to re-configure the service (monitoring server ip changes, etc.) although I know it's already installed this goes through the whole install procedure (of course faster now, but would be even faster if i could skip the entire procedure). Therefore it would be perfect to just call all necessary configuration steps.

Basically i took everything from the default.rb except the `include_recipe::_install` and put that into the configure.rb. The default.rb now also includes this configure recipe.

Let me know what you think about this.

Thanks in advance.