Since QDeclarativeNavigatorPrivate is what gets passed to the engine,
a QParameterizableObject *q becomes necessary in order to extract
and connect the QGeoMapParameters in the engines.

Change-Id: Id4a8a99f2287faab9c7e67e5355e9c90c33eaa8f
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>