Support extended AR QuickLook parameters when auto generating USDZ blob

[milesgreen]

Reference Issue

#3425

Approach

This change allows extended AR QuickLook parameters (EG custom, checkoutTitle, checkoutSubtitle, etc) to be appended after the src path as # hash fragment when using auto USDZ generation and there is no ios-src property.

Any / all defined # params get appended to USDZ blob without discrimination (AR QuickLook will ignore any invalid params).

Usage

Define src as something like:
https://example.com/model.gltf#custom=path-to-banner.html
Omit ios-src
Include "quick-look" in ar-modes to trigger auto USDZ generation.
When opening AR on iOS, USDZ will be auto generated and displayed with custom banner in AR.

Tests

Two tests created:

• replicate src hash to usdz blob url
• replicate src hash to usdz blob and set hash for fixed scale

Demo

https://modelviewer-auto-usdz-params.glitch.me/

Compatibility

Note that passing # params after blob url only works in Safari iOS 15.5 beta 4 onwards. Prior to that, passing # params after blob url were either ignored (https://bugs.webkit.org/show_bug.cgi?id=226265) or caused model to never load (https://bugs.webkit.org/show_bug.cgi?id=236069).

[milesgreen]

@elalish - please let me know if you'd like me to tackle in a different way.

I couldn't manage to get the unit test working though :(

[elalish]

Thanks! See, that wasn't so bad, was it? 😁

[elalish]

Looks great, thanks! I marked this as ready for review, because I think it's all done now, right?

[milesgreen]

Right. I think that's it...! If you're happy, I'm happy.