Clean-up and refactor WM Core build tools

[vkuznet]

Impact of the new feature
Unify and make complaint WM Core setup tools with Python PEP-625 requirements.

Is your feature request related to a problem? Please describe.
At the moment the WMCore codebase contains a mix of setup files which relies on different technologies, e.g.

• setup.py depends on distutils
• setup_template.py depends on setuptools
• setup_test.py depends on distutils
• setup_wmcore.py depends on setuptools

In addition the above files uses setup_build.py and setup_dependencies.py. Our GitHub Actions are using setup.py while tools/build_pypi_packages.sh uses setup_template.py to create its own version of setup.py.

It would be useful to streamline usage of different setup files, and settle down on one procedure used across GitHub Actions, build tools and docker files (which also contains mix of Dockerfile and Dockerfile.dist who use different setup files)

Describe the solution you'd like
This ticket should address three main issues:

• clarify, clean-up and refactor usage of setup files. We should converge on using setuptools as it is complaint with PEP-625
• perform clean-up of all Dockerfiles with CMSKubernetes/docker/pypi area to settle on single approach (Dockerfile vs Dockerfile.dist)
• and document build procedures in GitHub actions, building docker images and local deployment (if any)

Describe alternatives you've considered
Keep using all setup files as is

Additional context
This ticket is related to comply with PEP-625 requirements described in #12181