fix: WebXR examples

[capnmidnight]

Why

There are a number of incorrect type definitions in the WebXR examples code. In particular:

• ARButtons optional sessionInit constructor parameter is specified as any
• XRControllerModelFactory is missing an envMap field
• OculusHandModel and OculusHandPointerModel have a motionController field that is specified as Object3D, when a more specific type is avaiable
• XREstimatedLight's lightProbe field is specified as unknown
• XRHandModelFactory's createHandModel method's optional profile parameter includes "oculus" as a valid value, when that value has not been available for over a year.

What

• Change the ARButtons sessionInit constructor parameter to an extension of the XRSessionInit that provides for the option of specifying a domOverlay setting
• Add an envMap: Texture field to XRControllerModelFactory
• Change the motionController field in OculusHandModel and OculusHandPointerModel to be XRHandMeshModel
• Change the lightProbe field in XREstimatedLight's to be Three.js' LightProbe type.
• Change the profile parameter in XRHandModelFactory's createHandModel method's to accept "mesh" in place of "oculus"

Checklist

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

[capnmidnight]

So, I recently got a big change to the @types/webxr package to get them up to date. I've now modified my open PR here to include those types, as suggested in Issue #31.

[joshuaellis]

@Methuselah96 do you know why the CI is unhappy with this PR?

[Methuselah96]

@joshuaellis It's due to the change in package.json. yarn install needs to be run to update the lock file.

[capnmidnight]

I had committed the modified yarn.lock, but the CI complained about it. So I reverted it and the CI complained again. I just ran yarn install again and the changes this time are much less than last time, so I have committed it again.