QOS edit, create, and delete functionality

This builds on previous patches that adds QOS Spec functionality
to the "Volume Types" tab within the "Admin" -> "Volumes" panel.

Partially Implements: blueprint cinder-qos-specs

Change-Id: I0cc6447f279358f739bbdd3eff7f068b0b87ba09
Merge "QOS edit, create, and delete functionality"