Migrate to pyproject.toml and common workflows, update for numpy 2.0

[fsoubelet]

Next in the wave of PRs transitioning our packages to using the standard pyproject.toml file.

Important

The setup.py and setup.cfg files are gone. A pyproject.toml file now centralises everything, including metadata conformly to PEP621.

I have put down hatchling as a build backend, as it is the one developped by PyPA, the Python Packaging Authority, as they publish the authoritative user guide. This has little impact though, as any PEP518-compliant backend would work there instead.

Simple change to have numpy 2.0 compatibility.

Like for all other packages, this moves the minimum supported Python version to 3.9.

Details

I have put Hatch as a packaging tool as it is also the one from PyPA, but it is strictly optional. One does not need Hatch, because standards. The new common workflows (PR upcoming) don't even use it.

I have taken upon me to up minimum required versions (tfs-pandas for instance).

Additional

This PR also moves optics_functions to the common Github Actions workflows, and brings very minor lints.

[fsoubelet]

This requires a release after merge, to have a numpy 2 compatible version out there. I have updated version and changelog.

[fsoubelet]

As with other PRs where migration to common workflows was done, I will update the requested passing tests when the PR is accepted.