Speed up setuptools imports on Python 3.15+ by adding __lazy_modules__

[Avasam]

Summary of changes

Alternative dynamic mode: https://flake8-lazy.readthedocs.io/en/latest/cli/#dynamic-mode

Once pypa/distutils#414 is also merged, this will

• Close [BUG] SETUPTOOLS_USE_DISTUTILS=local makes any distutils import very slow #3585
• Close [BUG] Importing setuptools is slow and takes nearly half a second #3441

Autofixed by running

import glob, os, subprocess, sys
skip = {'tests', '_distutils', '_vendor', '_validate_pyproject'}
files = [f for f in glob.glob('setuptools/**/*.py', recursive=True) if not skip & set(f.split(os.sep))]
subprocess.check_call([sys.executable, '-m', 'flake8_lazy', *files, '--apply=set', '--strict-typing'])

Note: Merging #5222 first should reduce import reification related errors found by test.

Pull Request Checklist

• Changes have tests
• News fragment added in newsfragments/.
  (See documentation for details)

[mergify]

Tick the box to add this pull request to the merge queue (same as @mergifyio queue).

• Queue this pull request

[Avasam]

For tracking:

• Support __lazy_modules__ in lazy import rules astral-sh/ruff#25170
• Support and lints for lazy imports in Python 3.15+ astral-sh/ruff#21305

[Avasam]

This could be massively simplified with recursive globing support: henryiii/flake8-lazy#92