Suggest we rethink and eventually remove the use of URIs to identify resources

[cmoberg]

We make use of resource-id in a couple of places. Resource-id is of type inet:uri and is described to uniquely identify ports and other resources. YANG provides means of uniquely identifying instances using instance-id (http://tools.ietf.org/html/rfc6020#section-9.13).

An example of the use of resource-id is here: https://github.com/OpenNetworkingFoundation/configuration/blob/master/drafts/of-config.yang#L413