Faster twin renderer

[carolhmj]

This PR is a rearchitecture of the HTMLTwinRenderer, aiming to improve its speed.

Some PGs I tested with:
The ones in: https://doc.babylonjs.com/toolsAndResources/accessibility/screenReaders
Stress test: #C9GZTF#43
AddAllControls: #C9GZTF#49
Weapons demo with accessibility: #I6V1ST#240

[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/14441/merge

Test environment:
https://babylonsnapshots.z22.web.core.windows.net/refs/pull/14441/merge/index.html

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

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/14441/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/14441/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/14441/merge
https://gui.babylonjs.com/?snapshot=refs/pull/14441/merge
https://nme.babylonjs.com/?snapshot=refs/pull/14441/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/14441/merge#BCU1XR#0

[RaananW]

Let's discuss this offline :-)

[Popov72]

Mostly missing doc!

Generally speaking, there are a lot of checks with "instanceof", which is slow in javascript. If they're not in the hot path, then that's fine, otherwise I think you should try replacing them with something else (when possible), because as I understand it, this PR is intended to improve overall performance?