Adopt modern Python package method

[hongquan]

We have a Django project, which is meant to deploy on Linux server, and use uv as package manager. But some of our teammates use MacOS in development. One issue is that, when uv tries to resolve dependencies, it doesn't find enough dependency info of systemd-python (neither from PyPI nor from source dist), it has to build wheel file for systemd-python. This process has to be performed also on MacOS system, and then fails.

So, it would be nice if python-systemd project migrates to pyproject.toml file, so that this issue won't happen.

Thanks.