Add AEC design sandcastle examples

[r-veenstra]

Description

Implements three new Architecture, Engineering and Construction (AEC) related Sandcastle examples to support upcoming Cesium releases.

AEC Architectural Design.html demonstrates a typical architectural design model comprised of multiple tilesets with layer visibility toggles and metadata picking.

AEC Isolate by Category demonstrates how to use architectural categories embedded within the tileset metadata to isolate building elements such as doors, floors, stairs, etc.

AEC Metadata Styling.html demonstrates how to interactively style pipeing layers, highlighting pipes whose length falls within a min / max range controller by a UI widget.

Issue number and link

N/A

Testing plan

1. Review each sandcastle example
2. Ensure tilesets load appropriately
3. Ensure UI elements and any interactive functionality are working
4. Make sure the title, description and thumbnail are correct

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @r-veenstra! Welcome to the Cesium community!

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[ggetz]

Thanks @r-veenstra! I can confirm we have a CLA on file for you.

We'll review these shortly!

[ggetz]

@r-veenstra These examples are looking great! Is there any reason this PR is still in "Draft" as opposed to "Ready for Review"?

[r-veenstra]

@ggetz I just need to update the tilesets with some new ion asset ids, which I expect to do over the weekend. Once that's done, I'll move the PR to ready for review.