Prototype libwebsockets integration (for HTTP/S and WebSockets support)

[rdw-software]

Source: https://github.com/evo-lua/evo/issues/28

Goal: Implement HTTP, HTTP2, DNS, HTTPS, WS protocols in a way that's more secure/stable than rolling our own or relying on Luvit's implementation (and porting from Node is too risky/too much work)

Progress:

• [x] TBD: How to build libwebsockets against the OpenSSL version shipped with the runtime
• [ ] TBD: What APIs should be exposed?
• [ ] How can lws interact with the existing event loop?
• [ ] What parts of the libuv networking APIs should be covered by lws instead, if any?
• [ ] Write FFI bindings for the relevant APIs
• [ ] TBD: How to integrate lws into the build process?
• [ ] Write tests for the API surface? (not covering LWS functionality, just API interactions)
• [ ] What needs to be added to the CI workflow? Build lws, run test apps it provides, run API surface tests, Autobahn suite for WS, some other HTTP tests (apache), benchmarks/profiling tests, whatever Node has and uses?
• [ ] Any potential issues that may come up with integrating lws directly? (reasons not to do it)

[rdw-software]

Kinda stuck with this one; the documentation isn't great and there are some annoying issues:

1. libuv doesn't expose the event loop directly to Lua, so it can't be passed to libwebsockets
2. I can't get even the basic "hello world" example running via the ffi, since it keeps segaulting (presumably, there's no error) and I'm not familiar enough with the internals to understand what's wrong in a reasonable timeframe

I guess that means this is shelved until further notice. I'd still like to integrate lws, but I don't want to spend my free time bashing my head against these kinds of low-level problems if there's no sane way to debug the crashes.