Refactor Python precommit Docker setup

[LKreutzer]

Currently we build the Python precommit Docker image in CI in two workflows:

• .github/workflows/docker-builder-python-precommit.yml
• .github/workflows/python-workflow.yml

but never download it in CI, but only for local development.

• Is the upload actually needed?
• Should local usage also use a local build?
  • This may include a refactoring of precommit.py to make the --local behaviour the default.
• Should the .github/workflows/python-workflow.yml download the image instead of a local build?
• The following folders should be excluded from the local/CI check:
  • bazel-bin, bazel-out folders etc.
  • build folders
  • hil_testing
  • fabfile.py
  • setup.py

See: #14994