This property was intended to provide a way to have SSAO or VoxelGI
ambient occlusion with a color other than black. However, it was
dropped during the Vulkan renderer development due to the performance
overhead it caused when the feature wasn't used.
* Make sure shaders are named, to aid in debug in case of failure
* SceneRenderRD was being wrongly initialized (virtual functions being called when derivative class not initialized).
* Fixed some bugs resulting on the above being corrected.
* GIProbe is now VoxelGI
* BakedLightmap is now LightmapGI
As godot adds more ways to provide GI (as an example, SDFGI in 4.0), the different techniques (which have different pros/cons) need to be properly named to avoid confusion.
We've been using standard C library functions `memcpy`/`memset` for these since
2016 with 67f65f6639.
There was still the possibility for third-party platform ports to override the
definitions with a custom header, but this doesn't seem useful anymore.
