Add example involving JavaScript guest functions

[cloudspeech]

I am intrigued by this project, but can't help noting the lack of even remotely real-life examples. JavaScript is a popular choice for FaaS providers, cf. https://blog.cloudflare.com/introducing-cloudflare-workers/.

How about a worked example using e.g. Bellard's QuickJS?

Even if it showed only how to run user-defined math functions under Hyperlight, it would go a long way towards more realism.

Notes on how to add networking would be a big plus, of course.

[jeromegn]

I would also be interested in this.

I just played with hyperlight, but I couldn't get anything useful for running untrusted code in it. The no-std and "no libc" requirements prevent a lot of use cases. Out of the box, I wasn't able to get deno or rquickjs to compile under these conditions. I think rhai might be workable.

[kumargu]

On similar lines, can we have examples of JAVA guest functions? I saw the C execution of guest functions needed a FFI calls, do we need JNI bindings to call JAVA code?