Adding CRUD for roles

This adds basic support for CRUD on roles for admin users.

The CRUD operations in keystone are only exposed without an
extension in V3.  So if the python-keystoneclient does not support
V3, the panel will not be registered.

Support for blocking create, edit and delete in LDAP case added.

Implements: blueprint admin-role-crud

Change-Id: Ibd727df1392ab9a748ab585620c1ff3dc57d3efb
Merge "Adding CRUD for roles"