[XR] First version of Space Warp support

[RaananW]

This PR contains the XR feature that enables space warp, a feature available in the oculus browser (behind a flag). The feature was suggested as an official WebXR feature - https://pr-preview.s3.amazonaws.com/cabanier/layers/pull/303.html#feature-descriptor-space-warp as part of the XR Layers spec.

Note Code based on the initial version made by @dannysu

Closes #13945

[bjsplat]

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[bjsplat]

Snapshot stored with reference name:
refs/pull/13955/merge

Test environment:
https://babylonsnapshots.z22.web.core.windows.net/refs/pull/13955/merge/index.html

To test a playground add it to the URL, for example:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/13955/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/13955/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/13955/merge
https://gui.babylonjs.com/?snapshot=refs/pull/13955/merge
https://nme.babylonjs.com/?snapshot=refs/pull/13955/merge

To test the snapshot in the playground with a playground ID add it after the snapshot query string:

https://playground.babylonjs.com/?snapshot=refs/pull/13955/merge#BCU1XR#0

[sebavan]

LGTM but I am really wondering if we need the update in engine.multiview ?

[dannysu]

Thank you @RaananW! FYI, Meta Quest Browser v26.2+ has WebXR Space Warp on by default and doesn't require the flag to be toggled.

[carolhmj]

Nice! Just a couple of nits