In the neutron stadium, we maintain the networking API reference
in neutron-lib repository. It is different from other projects,
so it would be helpful for contributors if we have README in the
usual location (neutron/api-ref).
Depends-On: I6f2c4d476c31b252bfb181138505673f397639fc
Change-Id: I41dc58e5edfd18a52f13f042ba865b82fad764f7