a new policy xml export/import system, utilizes a genericized form that allows for
just passing nested python types [json like] (lists,dictionaries, etc,) to the exporter, and
getting the same back from the importer.
construction in turn follows from the python data structure, and is pluggable
by registering against a handler against path into the data structure.
compatibility for the new impl is in two stages, on old xml formats
we use the old parser for a release cycle, the old format is now depreceated.