Barbican/v2

Barbican v2

 * Use UUIDs for ID properties instead of URIs in references like the rest of OpenStack
 * Generic Container data structure is weird, consider making it a proper dict
 * Container term is confusing, consider
 * Use proper links for references rather than single 'ref' link returned now
 * Make order types match secret types
 * e.g. an AES-256 key is a "symmetric" type secret, but the order type to generate one is "key". It would be better (less confusing) if they were the same.