Extending quota support neutron LBaaS entities

Note: This change is a continuation of the abandoned
      change https://review.openstack.org/#/c/59192/
      Previous change was abandoned due to rebase problem.

Extending quota mechanism to support neutron
LBaaS entities. Adding quota for vips, pools, members
and health monitors.

This is one of four changes related to the BP.
This one is for python-neutronclient package.
Another one is for neutron project, another for tempest project
and another one for horizon/openstack-dashboard project.

See blueprint neutron-quota-extension for another two changes.

Change-Id: I2bfb974d513bd21b4dac6c90ddc6ede19797caf9
Implements: blueprint neutron-quota-extension
Remove unused imports

Remove unused imports in doc/source/conf.py

Change-Id: Ia21f8952b36ae74b1c2d3bfd10c0a4a04a390faa
Closes-Bug: #1265266
Merge "Extending quota support neutron LBaaS entities"
Merge "Remove unused imports"