Implement WASI Preview 2 Sockets

[lppedd]

I know you're already working (or will work) on supporting Preview 2.
It would be important to support the sockets component, both when targeting a runtime like Node.js, or the browser.

Use case: rewriting an extension which uses the Node.js net.Socket or tls.TLSSocket in WebAssembly.

Supported runtimes:

• Node.js: binding to TCP socket via Node.js APIs
• Browser: wrapping a WebSocket instance

[lppedd]

If async support is somehow necessary, it looks like WASI 0.3 will ship in March!
https://wasi.dev/roadmap#upcoming-wasi-03-releases