This introduces a new class QgsGeoTransform (derived from QTransform)
that keeps chunk's translation vector as a QgsVector3D (i.e. in double
coordinates) and if there is a shift of the origin, 3D map scene and
chunk entities react to it by adjusting the underlying QTransform.
Qgs3DMapScene.openScenes() will now return a map of
open Qgs3DMapScene objects (by name) visible in the app. Various
basic properties of the scene are exposed, including
the camera controller, allowing access to navigate 3d
scenes via python
