Allow Scripting with Rust Through WASM

[zicklag]

Right now we have support for scripting with Lua through piccolo, but it'd be great to also support "scripting" with Rust. By this we mean being able to load game code written in Rust from asset packs.

The ideal way to do this would probably be through WASM. While it is possible to support scripting by loading dynamically linked libraries ( i.e. .dll, .so, .dylib files ), these libraries are platform and CPU architecture specific, so it would mean that such mods would have to have different downloads for Windows, Mac, Linux, ARM, and x86_64.

Supporting WASM could also allow other languages such C ( and many others ) to be used for mods.

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TODO: I can give a more in-depth explanation of what this entails. If anybody's interested feel free to comment and I'll put some more info in here.