Test: Add integration tests to the repo

[Mossaka]

So far, we have implemented a working example, which compiles to a wasm module and can run by wasi-cloud CLI.

What we need is automated integration tests for the host implementations.

[Mossaka]

Here is a relevent convo on Teams with @khenidak and @danbugs

Problem: how can we automate test the guest application using wasi-cloud interfaces, at scale?

It is easy to start with a few guest applications, with a simple Makefile or build.rs to compile them to wasm modules, and load them to the host to tests. It becomes harder, however, if we want to have tens or hundres of wasm apps that describe various scenarios to test. There isn't a tool or framework integrated with wit-bindgen to allow us to parametrize the test functions. Even worse, we can't just write a function and test it. It has to contain a "main" function, and compile to wasm, and then load/link to the host runtim

looking into CI/CD tools like GH actions to resolve this...