Implement clustered lighting as a main lighting system (Root ticket)

This is the issue to track progress for the clustered lighting implementation in the engine. Here are the most important steps:

• Core tech prototype and architecture: https://github.com/playcanvas/engine/pull/2990
• Spot light shadows: https://github.com/playcanvas/engine/pull/3235
• Spot light cookies: https://github.com/playcanvas/engine/pull/3521
• Omni light shadows using the same shadow atlas as spot lights https://github.com/playcanvas/engine/pull/3537
• Omni light cookies using the same cookie atlas as spot lights https://github.com/playcanvas/engine/pull/3555
• Complete lighting model specular: https://github.com/playcanvas/engine/pull/3668
• Add support for area lights https://github.com/playcanvas/engine/pull/3691
• Shadow filtering options on top of default PCF3 https://github.com/playcanvas/engine/pull/3763
• Smarter texture atlas slot assignment https://github.com/playcanvas/engine/pull/3895
• Lightmapper update to use clustered lights https://github.com/playcanvas/engine/pull/3902
• Remove old lighting system (shader recompiles, uniforms, standard, static lights, chunks ..)

Optional features:

• Debug rendering of the cells and the number of lights in them https://github.com/playcanvas/engine/pull/3873
• Single texture slot solution to store prefiltered data for IBL https://github.com/playcanvas/engine/issues/3681
• Extract the light evaluation fragment function to standalone chunk to allow custom lighting models (cell shading ..)
• Optimize static light culling of static meshes to avoid shadow rendering if no change
• Tighter cone / sphere insertion into the cluster cells to limit number of lights in a cell
• Allow texture atlases for shadows and cookies to use texture array (light would store viewport and additional index)
• Consider moving parts of the work to compute shaders (filling in the volume texture with lights, and also filling in the lights data textures)

Other related PRs

• globally disable shadows or cookies: https://github.com/playcanvas/engine/pull/3567
• API https://github.com/playcanvas/engine/pull/3763

Public release after rounds of beta testing: https://github.com/playcanvas/engine/pull/4586