switch to using pyproject.toml

[Remi-Gau]

would be nice to switch pyproject.toml to centralize package metadata and tooling configs

[jasonnicholson]

This is a good idea.

[Remi-Gau]

from memory: remember that trying some of the more modern packaging methods via pyproject.toml was gonna work more easily when dropping support for older sphinx versions that assumed a slightly different way to organize sphinx extensions