Add WASM WASI backend

[AlecGhost]

The WASM WASI backend executes WASM directly in a VM, with access to the OS, instead of through Javascript.
The component model is used to compose a runtime with the Javalette program.

Note: I didn't get Docker running for this repo in the first place, so I only tested this locally on my Apple Silicon machine.

Tools required

• wasm-tools
• wac
• wasmtime

Setup

The tools expect the runtime.wasm to be a component.
The interface descriptions should be located in a folder named wit (relative to the path provided).
The wit file for the Javalette program must be located in the root of the wit dir and must contain a world named program.
The wit files for the runtime and its dependencies must be located in wit/deps/. It is advised to fetch them with the tool wit-deps to get the right files in the right places.

[AlecGhost]

I can also upload my runtime and wit folder to resources, if requested.