Keep world transform fixed when reparenting objects in Qt 3D Studio

Technical artists need to often reparent objects after importing or during the editing of the scene. Today this operation throws the transform (location and scale) totally off. We need to support reparenting while keeping the transform (e.g. the needle of the speedometer needs to say in correct place at correct size).

When creating parent- child structures the change of the parent should be automatically adjusted to child so that there is no need to adjust child transformation to get it to correct position (to adjust rotation etc to get it visible in correct size to correct position).