Adds glTF 2.1 features and GLB v3 (64-bit) support

[mklefrancois]

Description

This PR introduces comprehensive support for several new features specified in glTF 2.1. It also adds compatibility for GLB (glTF Binary) version 3, which utilizes 64-bit length fields, allowing for larger binary assets.

Key additions include:

• glTF 2.1 Features: Implements support for unique IDs (uid) for various top-level glTF entities (Animations, Skins, Samplers, Images, Textures, Materials, Cameras, Meshes, Nodes, Scenes, Lights). Adds structures and parsing/serialization for implicit shapes (Box, Sphere, Capsule, Cylinder, Plane) and bounding volumes attached to nodes. Integrates new accessor component types (HALF_FLOAT, INT64, UNSIGNED_INT64) and asset thumbnails.
• GLB v3 (64-bit) Support: Updates the GLB loader and writer to handle version 3 of the GLB format, which uses 64-bit length fields for chunks. This change enables the processing and creation of glTF binary files exceeding the previous 4GB limit imposed by 32-bit lengths.
• Type Safety: Updates internal function signatures to use size_t for buffer lengths, enhancing type safety and consistency, especially when dealing with potentially large 64-bit sizes.

Type of Change

• Bug fix
• New feature
• Refactoring (no functional changes)
• Documentation update
• Other (please describe):

[NBickford-NV]

Excellent merge request, by the way! It's fantastic to be so proactive about getting support for these new features, right out of the oven, into TinyGLTF. Note also the change to make TinyGLTF's MSYS2 CI work with the constraints of the limited set of GitHub actions we can use.