Add support for non-rust Wasm Modules

[afonsolage]

Due to component model isn't stabilized yet I'll postpone adding support for non-rust wasm modules.

When using rust wasm modules, we can just import bevy and use their methods directly on assembly, which is faster, but produces bigger wasm modules, due to code duplication.

When component model is available, we may able to have a single core module with all exported bevy types and functions and link those types and functions which any new created modules, reducing code duplication.