Wheels: Emscripten/wasm/Pyodide

[ax3l]

Once PyPI accepts them, we can build emscripten/wasm/Pyodide wheels.

cibuildwheels recently added support for it 🎉

[ax3l]

We tested compiles to WASM before with success #1199 #1201 and should target Pyodide for practical reasons (in-browser Python module execution).

Shipping directly in Pyodide is complicated pyodide/pyodide#2169 but PyPI wheels support would be ideal (scalable).