Store feature tables and feature textures as arrays to support EXT_mesh_features

[ptrgags]

Recently we've been revising EXT_feature_metadata. This has resulted in a newer draft of the schema, EXT_mesh_features.

One of the biggest changes is that metadata textures and tables are now defined with an array instead of a dictionary. This PR updates GltfLoader to handle this array-based storage.

This adds most support for EXT_mesh_features, however, I have not yet handled the differences in data type schema, I'll do that as a separate PR since this was already a ~2000 line change.

I also updated 3 of the test datasets (weather, microcosm, and box instanced) to use the new extension.

@sanjeetsuhag could you review?

CC: @lilleyse

[cesium-concierge]

Thanks for the pull request @ptrgags!

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  • If this change updates the public API in any way, please add a bullet point to CHANGES.md.

Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.

[sanjeetsuhag]

@ptrgags I have done a first pass over the code. Have not looked at the tests yet.

[ptrgags]

@sanjeetsuhag updated!

[ptrgags]

@sanjeetsuhag just synced with main to hopefully avoid those CI failures

[sanjeetsuhag]

Changes look good to me. Models are loading fine and picking works for both old and new extension.

@lilleyse Would you like to take a look before I merge?

[ptrgags]

@lilleyse at this point I've addressed your feedback, though I still have to go through and check test coverage to see what tests to add.

[ptrgags]

Coverage is pretty good, just a few places that need improvement

[ptrgags]

@lilleyse updated! I also opened #9884 for the "feature IDs without property table" handling.

[lilleyse]

Looks good!