Add git class and add defined function

Prior to this commit we did not manage git installation. This commit adds a new class that
installs git if its not already defined in the catalog. Also added a defined to mcollective service
Add POC r10k support

Prior to this commit I only had git support in the agent
This commit adds untested r10k support. This is really where this
module is going though I might add puppet-sync as well.