* Moves 3D Camera interpolation scene side.
* Automatically switches `get_camera_transform()` to report interpolated transform during `_process()`.
* Fixes `ClippedCamera` to work with physics interpolation.
Add scene side discrete level of detail.
New node `LOD` for UI, and `LODManager` within `World` for automatically updating child visibilities based on distance from cameras.
The data flow to the VisualServer of current and previous transforms is essential for allowing correct interpolation. An optimization was present that disabled sending transforms when nodes were hidden, however this meant that when unhidden, nodes would interpolate incorrectly from the last transform received when hiding, rather than the up to date previous transform.
This PR disables the optimization and sends always sends transforms when a node is interpolated.
