Removes the vendored in kube2sky built into the minikube binary and
replaces the dns solution with kube-dns cluster addon. This will allow
users to swap out DNS implementations by simply turning off the
kube-dns addon.
This introduces the minikube config get/set/unset command. At a basic level, it allows a more user friendly interface for setting minikube config values, but it also allows us to run validations and callbacks before and after the values have been set.