Added params class to start potentially handling default cases. Closes #8

@bobtfish  what do you think about this?


Defines can't inherit, so... I'm starting a params class that can get included *once*. This can reduce the total hiera lookups and potentially allow us to do logic about setting defaults for monitoring checks in hiera more easily (without breaking strict variables)

It also introduces the json to expose team data to other tools. 

I didn't do this on sensu_handlers because this is *client* side. There are some security implications but it is behind a toggle if inappropriate for the environment.