WebXR stuff

I've tinkered around with JanusWeb since the JanusVR days, but I wanna try a few other frameworks too. Here's a list of what I've tried so far.

As of the current versions of firefox (written 2023-10-12 12:05 PM) pointerlocking will drop down slowly when letterboxing is enabled. You will need to fullscreen.

Also I'm quite dumb, if there's anything incorrect below I'm pulling mostly from personal experience and vibes.