Faster assign lights to clusters using iterative sphere refinement method from Just Cause 3

[superdump]

As the number of point lights and clusters increases, so must the performance of the algorithm for assigning point lights to the clusters they affect. An efficient CPU-based algorithm that iteratively refines the radius of the sphere of influence of a light as it works through each cluster dimension has proven to provide a significant performance increase.

• https://github.com/superdump/bevy/tree/faster-assign-lights-to-clusters
• [Merged by Bors] - Faster assign lights to clusters #4345

[superdump]

Fixed by #4345 that was merged.