Adds Neutron LBaaS Support

Previously, kolla did not support neutron lbaas functionality.
Only Lbaasv2 is supported in Mitaka. Additional information can
be found here:
http://docs.openstack.org/mitaka/networking-guide/adv-config-lbaas.html


Magnum uses Neutron Lbaas to provide high availability to COE API
and Etcd endpoints within a bay. Therefore, Neutron Lbaas is required
for Kolla to support Magnum.

Co-Authored-By: Serguei Bezverkhi <sbezverk@cisco.com>
Partial-Bug: #1551992

Change-Id: I05360b7c447c601fcb3c2b6b2a913ef5cc0f3a1b