Add support for creating provider networks

Implements blueprint neutron-provider-networking

Change-Id: I4bad9483b92875ea5e143b0e11652e01faed35a4
Create an IPv6 network that uses an external router for IPv6

Change-Id: Id1498d74db816b3edbb8376ca5acb7cc5792ea5c
Update readme.md, heat is now enabled by default

Change-Id: Ia36879711aa440f4fba657159afeba2105c6aae4
Merge "Update readme.md, heat is now enabled by default"
Merge "Add support for creating provider networks"
Merge "Create an IPv6 network that uses an external router for IPv6"