Open Stack

Hello,

This initial patch [1]  allows to retrieve networks, subnets.

This is very easy, thanks to the graphene-sqlalchemy helper.

The edges, nodes layer might be confusing at first meanwhile they make 
the Schema Relay-compliant in order to offer re-fetching, pagination 
features out of the box.

The next priority is to set the unit test in order to implement mutations.

Could someone help provide a base in order to respect Neutron test 
requirements?


[1] https://review.openstack.org/#/c/574543/

Thanks,
Gilles