NORSPEC-291 WIP materials working underwater and in reflection and dis passes, not gamma correct, needs cleanup

NORSPEC-300 stop-gap measure of clamping offsets > 0 until server-side fix to store negative values can be released

NORSPEC-293 better fix incorporating srgb_to_linear curve and applying texture gamma corrections to spot inputs

NORSPEC-295 make a deferred path version of fullbright alpha mask shader so we can included gamma ops

NORSPEC-292 fix issues with managing LLNetworkData::PARAMS_LIGHT_IMAGE when demoting spotlights by removing their tex