SL-19653: Fix some vertex buffer data mask asserts

DRTVWR-559 Add "No Post" mode and refactor "Scene Gamma" into "Brightness" for adjusting legacy gamma when probe ambiance is 0 and dynamic exposure when probe ambiance is not zero.

Add buffer visulization

SL-19560 Revert hacky fix for other avatars having low res BoM textures.  Fix for brightening of PBR materials at the shadow horizon.

Value gets rounded towards closest increment, no point displaying smaller values

DRTVWR-559 Add control for automatic reflection probes to advanced preferences and featuretable. Remove Reflections checkbox.  Don't persist reflection probe volume display between sessions.  Incidental decruft.

TODO: Why did this work for the equivalent non-rigged prim?

DRTVWR-559 Balance night scenes against release, nudge glow down a smidge, remove exposure correction from legacy fullbright balance PBR materials against legacy.

DRTVWR-583