We move the shipping code in mixin's such that it can be applied on other
shipments.
We define properties to abstract the information needed by the create shipping
wizards. Such that they can be execute on any shipment.
issue9850
review324521002
We add the flake8 configuration used so we ensure everyone uses the same.
We remove the usage of __all__ for non public API.
When possible, we rationalize the class name according to its __name__ and module.
issue9082
review297061002