Implemented metadata core commands.
Updated VZ provider interface to use metadata.

* Previously the idea was to storea ll the VM information inside of the
  VM's ID, but that proved to be not such a great idea. Now there is
  metadata associated with each VM that is used to store the IP address
  and CTID and whatever else the providers need to store in order to do
  their jobs.
Implemented majority of VZProvider's prepare step