TS: Added types for WebXR

[repalash]

Added types for WebXR and fixed object types in WebXR related declaration files.
Related to issue #20041

Types are adapted from these files.

• model-viewer: https://github.com/google/model-viewer/blob/master/packages/model-viewer/src/types/webxr.ts
• babylon.js: https://github.com/BabylonJS/Babylon.js/blob/master/src/LibDeclarations/webxr.d.ts

[mrdoob]

I think I would move the file to src/renderers/webxr/webxr.d.ts.

[repalash]

@mrdoob I figured since it doesn't declare types for any three.js specific module, it should be put it extras. Do you think I should move it to src/renderers/webxr?

Also, I haven't exported these types in Three.d.ts, should that be done? Would it be useful?

[mrdoob]

@mrdoob I figured since it doesn't declare types for any three.js specific module, it should be put it extras. Do you think I should move it to src/renderers/webxr?

I think so yes.

Also, I haven't exported these types in Three.d.ts, should that be done? Would it be useful?

No idea, I have no experience with Typescript...

[mrdoob]

Looking good!

Just a few linting warnings. Are these fixable?
https://github.com/mrdoob/three.js/pull/20150/files

[repalash]

Yeah, fixed.

[mrdoob]

Thanks!