Marconi message queue resource implementation

This implements a Marconi backed native OpenStack message queue. Customers
can create a OS::Marconi::Queue queue resource declaratively in templates
and pass the href/endpoint of the queue to other resources by means of href
attribute of the queue.

Marconi bp,
https://blueprints.launchpad.net/marconi/+spec/heat-template

Implements: blueprint mqaas-marconi-resource

Change-Id: Icbbb1869b352dbdba22530f9ec185652f4da75b6
Merge "Marconi message queue resource implementation"