Fix T83300: constant scene refreshing in Cycles with empty volumes

This infinite loop is caused by a conflict between the volume mesh
creation which unintentionally clears the shaders before early exiting
when no grid is found, and the Blender exporter which adds back the
shaders causing us to reupdate as the shaders changed.

To fix this simply preserve the shaders on the Volume node.

temporarily disable TLAS refitting as it fails when we refit curves

alembic: add hair data to the cache

remove partial support for motion blur

This would need persistent data for final renders, or at least a way to
tell which frames to load.

only use procedural for viewport renders

alembic: remove logic to reload data if already consummed

Simply copy the arrays while waiting for support for reference counting
on the arrays.

cleanup, remove comment

format

cleanup, encapsulate ProceduralManager

cleanup, includes