Remove old b3dm/i3dm/pnts content classes

[ptrgags]

As part of #10346, this PR removes Batched3DModel3DTileContent, Instanced3DModel3DTileContent and PointCloud3DTileContent. Model3DTileContent will be used instead.

A couple of notes:

• I also removed specs for b3dm classification, as Make ModelExperimental handle classification #10623 will handle this
• I disabled the tests for Cesium3DTileBatchTable until we can consolidate that with ModelFeatureTable, since the tests used b3dm files which no longer use the old style of batch table (only .vctr and .geom do)

@j9liu could you review?

[cesium-concierge]

Thanks for the pull request @ptrgags!

• ✔️ Signed CLA found.

Reviewers, don't forget to make sure that:

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

[ptrgags]

@j9liu I checked the Sandcastles and they're all good except for the ones with the BIM model (since that change is only on main). I'm going to merge main -> replace-model then replace-model -> remove-1.0-contents so we can better test those Sandcastles.

[ptrgags]

@j9liu okay, the Sandcastles with the BIM tileset should work correctly now!

[j9liu]

@ptrgags looks good for the most part, just a few comments!

I'll run through the Sandcastles locally as well to make sure no new bugs came up

[ptrgags]

@j9liu oops forgot to mention the PR is ready for review again!

[j9liu]

I found a regression but I don't think it has to hold up this PR. In the 3D Tiles Formats sandcastle, PointCloudDraco isn't properly responding to the "Debug Colorize" option in the inspector:

For reference, this is what it does on sandcastle.com right now:

Everything else looks good. Thanks @ptrgags !