Endpoints: Add create, delete, list support
    
    This adds the ability for admins to list, create and delete
    endpoints in the service catalog.
    
    New endpoints can be created and associated with an existing
    service, similar to the original Keystone.
    
    The current, file-backed templated catalog driver does not support these
    actions.  This requires that the SQL catalog backend is merged:
    
    https://review.openstack.org/#change,4464
    
    Update: As per discussion on above review, Remove use of OS-KSADM key,
            update tests accordingly.
    
    Change-Id: Ie6f219fe989327bd61e293ce100b70dbf7f6de52