Fix loading glTF ZIP files in the editor

Examples: Clean up.

Docs/Examples: Implemented dark mode support.

Editor: Replaced color theme logic with CSS color-scheme. 

Docs: Clean up.

Examples: Remove EquirectangularToCubeGenerator.

PointsMaterial: add alphaMap support

Docs: Clean up.

GLTFLoader: Use extensionName for extensions[] access consistently

This is a minor cleanup - two of 5 extensions spelled out the extension
name twice, one as a case label and once as an array index.

Accept number in BufferAttribute definitions

Docs: Clarify Mesh.drawMode.

Fix some TypeScript definitions

Corrected typo in Spherical: axiz -> axis

Examples: Make domElement to a mandatory parameter for all controls.

ObjLoader2Parser materials are not applied in worker

#17615 Fix material assignment when Parser is run in worker. Additionally, allow material override from OBJLoader2.addMaterials to MaterialHandler.addMaterials

Fix for TypeScript - optional parameter in WebVR.d.ts