Templated catalog backend not implemented

The templated catalog backend is not all implemented. Functions like:

- endpoint list
- endpoint get (show)
- region list
- region get (show)
- service list
- service get (show)

Are not implemented, they are delegating on KVS catalog backend.

When you call them from python-keystoneclient or python-openstackclient,
this calls are delegated on the Templated superclass, i.e., Kvs class.
The problem is Templated backend has obtained all the info about the
endpoints (reading default_catalog.templates file on __init__ function)
but Kvs backend doesn't have any idea about that, so that calls always
returns empty.

Change-Id: Iee2f888185125ea25d4ffda8a487553510635f76
Closes-Bug: #1367113