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.

pyproject.toml

@@ -77,8 +77,10 @@ requires = [
 ]
 build-backend = "setuptools.build_meta"
 
-[tool.setuptools]
-packages = ["pystencils"]
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["pystencils", "pystencils.*"]
+namespaces = false
 
 [tool.versioneer]
 # See the docstring in versioneer.py for instructions. Note that you must