Implement base for Walrus WASI

[kulcsaradam]

I have started working on implemeting WASI in Walrus.

As I have seen WASI is in a change right now where they are abandoning their witx format for wit. They are in a constant change and it could be troublesome to import other WASI systems in Walrus, as all other WebAssembly runtimes implemented their own version too as I have seen (on the basis of the official c-api).

This base can help us start implementing our own version too. This is just a rough base though, and needs some working.

My basic thought were:

• only import functions that are used by the module

• have a constant list with our implemented functions (this needs work, but I am open to other structures too)

• be easily expendable

The function list right now is just for example, I do not mean to actually implement it this way.

[kulcsaradam]

Please give your insgihts on this if this is an accpetable approach @ksh8281 @clover2123 @zherczeg .

[clover2123]

It looks good to support Wasi as Wasi functions are widely used. But, IMHO implementing JITC and SIMD have the highest priority now Of course, it would be great if Wasi is supported together while JITC and SIMD are updated too

@zherczeg I wonder your opinion and development plan as well

[kulcsaradam]

It was closed by mistake.

[kulcsaradam]

@clover2123 please check out this version of a base for wasi.