TCP/UDP support with W3C Direct Sockets API

[Minigugus]

It looks like TCP/UDP will finally be possible after all, even without a server! https://wicg.github.io/direct-sockets/#abstract 🎉

Obviously for security reasons, it will only work in Isolated Web Apps, but it's a really good news for many use cases like MMORPGs for instance 😃

Chrome/Chromium already actively working on it (https://chromestatus.com/feature/6398297361088512), and there's even a working demo: https://github.com/GoogleChromeLabs/telnet-client#readme

Related: #905 #2462 #2151

(I created another discussion for visibility, and to avoid reopening old subjects)