add lint, mypy config

[codecakes]

Setup linting and mypy configuration.
Make sure mypy configuration is added in pyproject.toml See this for reference:

# See: https://github.com/python/mypy/issues/5205
# mypy global options:
[tool.mypy]
python_version = "3.9"
plugins = ["pydantic.mypy"]
# See: https://blog.wolt.com/engineering/2021/09/30/professional-grade-mypy-configuration/
disallow_untyped_defs = true
check_untyped_defs = true
disallow_any_unimported = true
ignore_missing_imports = false
no_implicit_optional = true
warn_return_any = true
show_error_codes = true
warn_unused_ignores = true

# See: https://pydantic-docs.helpmanual.io/mypy_plugin/
# mypy per-module options:
[tool.pydantic-mypy]
init_typed = true