Revert migration of setup to pyproject.toml
# What does this PR do?

As mentioned in #22599, the migration of the setup to pyproject is causing some issues for editable installs on some setups. This PR reverts that migration and adds the setup.py to the formatted files. (Note that I could not directly revert the original PR due to some of its changes being already reverted in #22587 )

Fixes #22599 
_The documentation is not available anymore as the PR was closed or merged._