Replace server.nics with server.addresses to only return basic
addresses info with server API object, and we also provide an
API to get networks infomation.
Now Mogan can support network_ids in request of creation servers.
This feature introduces the support for specifying the port_ids
in request body too.
Implements: bp specify-neutron-port-when-creating-instances
1. Change to return 204 (No Content), as the POST method doesn't
result in a resource that can be identified by a URL
2. Add API docs for associate fip API.
Support to create multi-instance in one request of mogan.
This commit finish the main flows and leave some network check
for another commit.
Implements: bp support-multiple-creation