build,python: Build Python bindings without distutils
* m4/python.m4: Add python3.12 and 3.11 as valid interpreters, remove EOL 3.4, 3.5, 3.7 (keep 3.6 because some distributions still ship and maintain it). * lang/python/Makefile.am (clean-local): Remove dist and gpg.egg-info created by Python 3.9+ on make install. * lang/python/setup.py.in: switch from distutils to setuptools where possible, remove obsolete and deprecated -py3 option of swig, add classifiers up to 3.12, remove 3.4, 3.5, 3.7. * lang/python/doc/src/gpgme-python-howto.org: replace distutils with setuptools * lang/python/examples/howto/advanced/cython/setup.py: replace distutils with setuptools
This fixes building the Python bindings for Python 3.12 where distutils
has been removed.
Based on D545