Set up pre-commit hooks

- add pre-commit hooks:
  + run `nox -s lint` on staged *.py files
  + run common pre-commit hooks for validations that could not be
    achieved with tools in the develop environment so easily
- add pre-merge hook:
  + run `nox -s _pre-commit-test-hook` before merges
    * ignores the paths to staged files
      passed in by the pre-commit framework
    * runs all test cases instead