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.

MANIFEST.in

-include README.md
-include COPYING.txt
 include AUTHORS.txt
 include CONTRIBUTING.md
-CHANGELOG.md
-global-include *.pyx
-include versioneer.py
-include pystencils/_version.py
+include CHANGELOG.md