use only pyproject configuration

[tomkralidis]

This PR:

• moves to using pyproject.toml exclusively for project configuration
• removes setup.py and related artifacts
• note that in pyproject.toml we pin setuptools to <69 for Ubuntu 24.04 compatibility

This PR also contains some test updates (note that the changes in tests/test_wfs_generic.py are due to the remote WFS service error'ing out on DescribeFeatureType requests only in WFS 1.0.0 mode; test is removed given we support WFS 1.1.0 and 2.0.0 proper).

[geographika]

@tomkralidis - I checked out this branch and built locally. All runs fine, but the wheel is missing all the subpackages of owslib. Image on the left is the new wheel, on the right the latest on pypi:

I tried adding the following, but for some reason the tests folder still gets added to the sdist .tar.gz (which didn't include it before).

#[tool.setuptools]
#packages = ["owslib"]

# find all subpackages automatically
[tool.setuptools.packages.find]
where = ["owslib"]

Some related long discussions at pypa/setuptools#3346 - maybe this is fixed in newer setuptools? Have you run into it before?

[tomkralidis]

@geographika it turns out that MANIFEST.in helps here (removing tests/). Let me know if dist/ is now fixed on build.