Cinder Nested Quota Driver

Cinder Nested Quota Driver

Cinder Nested Quota Driver patch adds hierarchical support. Quota
API's now can also handle hierarchical projects.

For the first pass only a user with admin role in a parent project
will be able to update and delete its children quotas.

Even after these changes are made, the existing DbQuotaDriver
functionalities will remain unchanged. The same driver will be able to
handle flat projects as well as hierarchical projects.

Co-Authored-By: Erickson Santos <erickson@lsd.ufcg.edu.br>
Change-Id: Ie669d7d74d40c0ff1f1e54f673e7f3ae96b3b950
Implements: bp cinder-nested-quota-driver