Although I know this not follows best practices, this huge commit
reorganizes and defines the mail functionality for the rest of the
plugin refactor work:
* Renames and moves tasks to puppet/manifests/midonet-* names
* Stops, reconfigures and restarts Neutron
* Makes DHCP and metadata work
* Improves documentation
Change-Id: I6d5ed20ba212a089b808c09fe50a8aedaab74721