Use numpy docstring style

Change all docstrings to numpy docstring format and check docstring with pydocstyle on CI (and if it is possible using pre-commit)

some refs: 

- https://numpydoc.readthedocs.io/en/latest/format.html
- https://github.com/ibis-project/ibis/blob/master/.github/workflows/main.yml#L226
- https://github.com/ibis-project/ibis/blob/master/setup.cfg#L14