Optimization: Clustered lights and geometry

[Nielsbishere]

Would increase performance a lot for shadows and primaries.

[Nielsbishere]

Idea:
Light BVH for frustum culling
Frustum culling
Tile culling

Problem:
Omnidirectional and stereo requires 360 or 2 viewports, so tiles aren't possible. These would be more of a cone in these examples or a cone-shaped frustum.