Use rpc and notify transport_url for oslo_messaging backends

Use rpc and notify transport_url for oslo_messaging backends

This commit adds the transport_url for specifying the oslo.messaging
rpc and notify transport schemes. The rpc or notification backend
can be one of rabbit, amqp, zmq, etc. Oslo.messaging is deprecating
the host, port and auth configuration options. All drivers will
get the options via the transport_url.

This patch:
* Adds transport_url to base services
* Updates the corresponding specs
* Adds to default hierdata

Depends-On: I1cf93d2caebfa1f7373c16754a2ad9bd15eb1a40

Change-Id: Iea5607dbb3ee6b1dd50acc1395de52dc920aa915