Fog Fix (#1661)
* Some lightbinner cleanup, allow it to be used directly without the complex system that scenesystem wants
* VolumetricFogRenderer has it's own lightbinner outside of lightbinner pool, does lightbinning to fetch fog lights for the fog context only, fixes fog light settings not doing anything, deprecate LAYERFLAGS_NEEDS_FOG_CONTRIBUTING_LIGHTS since we don't need special code for that anymore
* Share dynamic shadow atlas if we have more than one lightbinner per view ( for example, fog ), fix volume fog no shadows option, cleanup unused shit
* Put fog mode in it's own category and add nice icons to them
https://files.facepunch.com/sam/1b0611b1/zwd8qAJFu7.png
* These convars don't do anything or are redundant, some notes for tiled rendering in the future
* Remove deprecated VR stuff for volumetric fog on rendering pipeline, note for Alex that we can just reproject the frame for eye 2 for cheap volumetric fog rendering, any crumbs will be stripped more when I remove clipmaps
* One lightbinner per volumetric fog rather than creating it every frame
* Start removing fog clipmap rendering, there are better ways to do this and it's massive
* Disable clipmaps on managed code, clean up shader code
* Remove VR-specific frustum stuff from volumetric fog
* Get rid of redundant data
* Separate two passes cleanly, remove accumulation TAA, we'll do a proper big pants one
* TAA stub
* Fancy volumetric fog taa, move what was on integration step to previous pass, so this has pretty much the same cost and memory footprint as previously but much higher quality
* Proper fog TAA with ping-ponging accumulation textures
* Iterate fog denoising
* Do soft TAA jitter and encode non-final texture to a softer color space so that TAA bbox is also softer
* Final cleanup, fix fog density, fix obsolete error
