Split player engines into separate WASM bundles

[mmontag]

Right now, the player engines are bundled into one large (~1.3 MB) chip-core.wasm module. We should try to split the player engines into separate WASM bundles without incurring the overhead of loading a separate Emscripten runtime for each engine. This may be possible with Emscripten dynamic linking (or something simpler).

https://github.com/emscripten-core/emscripten/wiki/Linking#hyper-dynamic-linking