Get Third Room working on GitHub Pages

[robertlong]

We're using netlify right now, but it'd be great if anyone could fork the repo and instantly have a working client and build system set up. GitHub Pages doesn't have a way that I know of to add COOP/COEP headers though. We should look into whether there's a zero config option to host after forking.

One possibility I found is to use a ServiceWorker. There are some limitations as you need to ensure that the the page is served via the ServiceWorker before it can load a script with SharedArrayBuffe, but I think we could work around that. https://dev.to/stefnotch/enabling-coop-coep-without-touching-the-server-2d3n