GitLab

Initialize setup.py and basic configurations for this project.

Major revisions:

- initialize setup.py for Python package
- add gitignore and dockerignore
- add editorconfig for editors
- configure yapf for auto formating
- configure mypy for type hint
- configure flake8 for lint, including quotes and docstrings
- add pre-commit check for `git commit`
- add spelling check in GitHub Actions
- format existing files according to configured rules

Example usage:

    # install dependencies
    $ python3 -m pip install -e .[dev,test]
    $ pre-commit install

    # format code automatically
    $ python3 setup.py format

    # lint code
    $ python3 setup.py lint

    # test code
    $ python3 setup.py test