updated to support chef-provisioning

Intentionally left default ec2 key pair and ssh key names untouched.  I'll leave that to some one in ops to do when they are prepared.

recipe renames:
metal => chef-provisioning
metal-clean => cluster-clean
metal-provision => cluster-provision

updated to use chef-provisioning-fog and new require path
Let's just call this recipe '`provisioning`'. We have chef in the cookbook name :ice_cream: