Refactored ip_retention and ip_retention_container models and node_api's.
Minor code cleanup in dp_info and datapath.
Removed item_by_params alias for internal_retrieve.
Refactoring of network and network_service models and node_api's.
Refactored route_links models and node_api's.
Refactored security_group_interfaces.
Refactored translation models and node_api.
General cleanup of models.
Fixed route link event name.