Add MaterialX Equivalency Check

[kwokcb]

Issue

There is no functional equivalency check for MTLX->gltf->MTLX validation.

Tasks

• Add functionality for 1.39.2
  • Write functionality
  • Merge logic to main: Add Element Equivalence Interfaces AcademySoftwareFoundation/MaterialX#2003
  • Add logic to ignore comments: Skip comments in functional equivalence tests AcademySoftwareFoundation/MaterialX#2110
  • Clean up options struct: Cleanup options for equivalence testing AcademySoftwareFoundation/MaterialX#2115
• Update testing framework to perform round-trip mtlx compare when glTF -> MTLX logic in.
  • Current logic being checked with explicit comment removal.
  • Remove comment removal pre-process as this is handled in PR 2110.
• On official PyPi release , bump the converter minimum version to 1.39.2. (Tentative December, 2024 time frame)