POC: Add proxy as an alternative to Browser extension

I've been working with reverse proxies the last week and I think it would be useful to implement one here.

Via NGINX + OpenResty we can:

Modify the headers of the page (enabling inline scripts, or allowing to put it in an iframe, and much more that maybe can't be done with a simple browser extension)
Inject the dom3d.js script via body_filter_by_lua_file
Make the browser believe the page domain is actually the requested
Deploy somewhere and make these amazing 3D websites public :)

This PR also includes a Dockerfile to easily run it, and a fly.toml as an example on how to deploy it.

I've deployed one. Here are a few examples:

This is just a POC. If you think it could be useful, would love to add more docs.

Here you can setup locally:

Build: docker build -t nginx-proxy -f proxy/Dockerfile . (we need it to be from main directory so we have access to the dom3d.js file)
Run: docker run -p 9000:80 -it nginx-proxy (port 80 mapped to 9000)
Go to localhost:9000/p?uri=example.com

If you want to deploy, install the flyctl CLI and use fly launch --dockerfile proxy/Dockerfile

Screenshots:

OrionReed / dom3d