Add proper version to QtPositioning and its QML API.

The QML API remains available under 5.0 though.

Change-Id: I037b82e5b12825db610e8458d6c82122ecde4f44
Reviewed-by: Erik Mattsson <erik.mattsson@appello.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>