Fix breakage in setuptools-69.0.0 by cleaning up setup.py

Patch received via email:

Hello,

Setuptools 69.0.0 deprecated a bunch stuff leading to a nasty errors during install.

File "/tmp/pip-build-env-w815o5v3/overlay/lib/python3.11/site-packages/setuptools/config/_apply_pyprojecttoml.py", line 183, in _license
         _set_config(dist, "license", val["text"])
                                      ~~~^^^^^^^^
KeyError: 'text'
[end of output]

version.py wasn't used anywhere except setup.py so removing and setting it all pyproject.toml is safe.

During this decided to move as much as I could out of setup.py, zip-safe has been obsolete for modern setuptools installation methods so dropped it.