LPS-42397 Add staged model data handler to support DDLRecord export/import
LPS-42397 Register SMDH
LPS-42397 Add DDLRecord support to DDLPortletDataHandler
LPS-42397 Propagate system events when deleting records
LPS-42397 Add test
LPS-42397 Language key
LPS-42397 Partially unrelated - Shows the actual preference value on the configuration screen istead of the calculated value because its confusing when staging