Add quantum_subnet custom type.

Change-Id: I489f0d9a10dfad2d19c491fb55efe449899d8c40
Add quantum_router custom type.

Change-Id: Ie00b839dc10c1e7b0a14801ad51fc483c7457c65
Add quantum_router_interface custom type.

Change-Id: I0f3eb0ec30247932564eb1b65bd08bd75d87c481
Merge "Add quantum_subnet custom type."
Merge "Add quantum_router custom type."
Merge "Add quantum_router_interface custom type."