David Runge authored
arch_release_promotion/config.py: Change `Settings.PRIVATE_TOKEN` to become an optional attribute, as it is not required for readonly scenarios. Order all `Settings` attributes alphabetically and add documentation for them and their respective default values. Change `Settings.validate_private_token()` to reflect the change in type for `Settings.PRIVATE_TOKEN`. tests/test_config.py: Extend tests to also check for cases where `Settings.PRIVATE_TOKEN` is None.