maturin is a Python build tool (written in Rust),
that can robustly handle building Python packages with UniFFI bindings.

This gets rid of our highly custom `setup.py` setup,
streamlines development and building of the Python package
and ensures consistent generation of Wheel packages for release.

This also combines all Python configuration into a single place:
a top-level pyproject.toml

This breaks with the new setup.
We're down to only 2 direct dependencies. We're "fine" for now