chore(WebXRManager): add missing methods, update getCamera signature

[CodyJasonBennett]

Why

Some changes to WebXRManager's signature weren't tracked with mrdoob/three.js#21886 and various other changes with the introduction of layers and controllers.

What

This PR updates the getCamera signature to return an XRCamera and introduces low-level getBaseLayer, getBinding, getFrame, updateCamera, and setReferenceSpace methods. I've vendored Babylon's WebXR types and updated WebXRManager and WebXRController.

Checklist

• Checked the target branch (current goes master, next goes dev)
• Added myself to contributors table
• Ready to be merged

[tongtwist]

I needed these types updates too.
Everything sounds good to me.
Btw, with these changes, types better reflects the r140 documentation of WebXRManager.getCamera()

[CodyJasonBennett]

I went ahead and fixed the webxr types and completed three's controller types.

Notably, this drops WebGLRenderingContext#makeXRCompatible and swaps XRGamepad for the native Gamepad.

[joshuaellis]

@0b5vr if you approve I will merge this.

[joshuaellis]

#218 merged added @types/webxr i'm wondering if this is still necessary? If so, the merge conflicts will need to be resolved.

[CodyJasonBennett]

The changes in my PR were more correct than @types/webxr and still Babylon. I'd need to find time to review.

[0b5vr]

@0b5vr if you approve I will merge this.

I didn't noticed to this! Let me see this real quick.

[CodyJasonBennett]

The updated @types/webxr look good to me. I'll revert related changes in my PR, but #218 didn't touch the three interfaces I originally corrected here.

Am I correct in assuming that these types are ambient? I've removed imports to the WebXR definitions accordingly.

[joshuaellis]

cc @CodyJasonBennett see above comment

[joshuaellis]

Thanks for all your work @CodyJasonBennett & thanks for the reviewing @0b5vr.