Changelog:

• Modernize project
  • Converted project from setup.py do pyproject.toml
  • Changed build command from python setup.py sdist to python -m build
  • Add ruff and mypy to replace flake8 and pylint
  • Pin Python version to simplify working with tools like uv
• Set default Splunk version to latest
• Add an .env.template to repo
• Update external GitHub Actions and pin them to specific commits (extracted to separate PR)
• Update CI target matrix:
  • Replace Splunk 8.1 and 8.2 with 9.3 (most widely version used according to SkyNet)