Add wasm

[thewh1teagle]

https://developer.mozilla.org/en-US/docs/WebAssembly/Rust_to_Wasm

Unsupported architecture. something wrong with the cmake invoking to compile speex to wasm target

todo:
Try with sample program, try compile speex directly to wasm with cmake. (works)

Compiled manually with:

rm -rf build
emcmake cmake -B build -G "Unix Makefiles"
cmake --build build

Bindgen doesn't generate the bindings correctly. missing functions

rust-lang/rust-bindgen#2989

Wasm pack failed to compile with CMake. rustwasm/wasm-pack#1455

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Added wasm with emscripten