[Feature] Determine IPD from WebXR APIs to send to Server

[vmohan7]

Similar to how we are able to calculate the VR Display Size with WebXR and send to the server, we should do the same for IPD as that will allow us that ability to fine tune the visuals from the SDK to match the user preferences.

[machenmusik]

Blast from the past: https://quest-ipd.glitch.me/ Hope it helps!