Refactor packaging, part I

Relates to #75 (closed).

Move all project info to pyproject.toml.

Tasks:

• Static Project Info
• Register and run versioneer
• Register Cython extension modules
• Clean up package data files & manifest
• Remove quicktest action from setup.py and realize quicktests some other way -> introduced quicktest.py

Notes:

• The quicktest command in setup.py uses the distutils command interface, but distutils is deprecated since Python 3.10. We must find some other way to realize quicktests.

requested review from @holzer

assigned to @da15siwa

mentioned in merge request !362 (merged)

changed the description

approved this merge request

mentioned in commit da2d8c46

merged