Added bounding box tests

[javagl]

Some test cases for proper handling of bounding boxes from glTF assets, taking into account the y-up-to-z-up transform, and including some code snippets for computing the proper boundingVolume.box from the bounds of a glTF asset.

Preview: https://github.com/javagl/3d-tiles-samples/tree/add-bounding-box-tests/next/BoundingBoxTests

[lilleyse]

Nice! This will save hours of frustration... I hope 😄

• Update the JS code (template strings, CesiumJS local function style, let/const, formatting, and anything else that came up in Added MetadataGranularities example for 3D Tiles 1.1 #43)
• Now that 3D Tiles 1.1 is stable-ish, update to 1.1

[javagl]

This PR is obsolete: #45 contains the addition of the model itself, and the feedback from this PR.