4.2

[BradyAJohnston]

Implement changes for compatibility with Blender 4.2

Current build is approved and hosted on the extensions website - need to finish final changes before 4.2 release (https://extensions.blender.org/add-ons/molecularnodes/)

• [x] Change to distribution via the Blender Extensions platform (#500)
• [x] Add support for 4x4 matrix data format (#499)
• [x] Change node groups to using colors and add descriptions (#522)
• [x] Test cleanout of superfluous .whl files (like numpy, which is included with Blender)
• [x] Refactor MD selections to be 'live' rather than only on import (#466)
• [ ] All relevant documentation is updated
• [x] Update default materials and include some more (#465)
• [ ] Update tests to run by building and installing the add-on
• [x] Change panel to use new panel code

Some feedback from extensions approval:

• [x] Cleanup commented out lines of the blender_manifest.toml
• [x] .DS_store and some other files can be cleaned up (potentially download .whl files then use Blender to build package)
• [x] remove requirements.txt file as no longer needed for package management