Running `setup.py` as a script and its use as a CLI tool are deprecated

[Avasam]

https://packaging.python.org/en/latest/discussions/setup-py-deprecated/#is-setup-py-deprecated

python setup.py and the use of setup.py as a command line tool are deprecated

https://setuptools.pypa.io/en/latest/deprecated/commands.html#running-setuptools-commands

running python setup.py directly as a script is considered deprecated.

pywin32 itself should move away from it, I have yet to investigate everything needed for pywin32 to move away from it.

Relates to #2119

To stop using python setup.py, the --skip-verstamp flag needs to be changed. Either trying to pass it through:

• --config-settings and --build-option / --global-option
• Environment variables
• Change version stamping to not have a bootstrapping issue in the first place, rendering this flag obsolete.
• or another mechanism I'm not aware of

Being able to build / install from pip install will open the door to:

• Building / installing the latest in-development version directly from a GitHub branch Unable to install directly from Git via pip #2306
• editable installs, which itself:
  • Allows developer to test/import modules directly from the repo https://setuptools.pypa.io/en/latest/userguide/development_mode.html
  • Helps static checkers be more aware of which files should be present, during development.

    pywin32/pyrightconfig.json

    Lines 45 to 51 in 9ef5061

    	// Too many dynamically generated modules. This will require type stubs to properly fix.
    	"reportMissingImports": "warning",
    	// IDEM, but happens when pywin32 is not in site-packages but module is found from typeshed.
    	// TODO: Is intended to be fixed with an editable install
    	// Since we're a library, and not user code, we care less about forgetting to install a dependency,
    	// as long as we have its stubs. So just disabling for now is fine.
    	"reportMissingModuleSource": "none",