Add support for Pyodide/WASM builds

[apcamargo]

Since Pyodide 0.31.4, WASM wheels can be uploaded directly to PyPI. This simplifies distributing packages for Pyodide, and cibuildwheel already provides support for building and publishing these wheels (I'm still investigating the best approach for enabling Pyodide builds in CI for Maturin-based projects).

It would be great if python-project-generator could provide built-in support for generating projects with Pyodide build configuration.

[sanders41]

I don't personally have a use for this, but if you do and want to work on it I'm open to adding it.