Feature: Support stacking lip notches

[Dooez]

An implementation of notches for stacking lip to prevent slipping of smaller bins when placed on top of longer bins.
Only rectangular bins are supported because custom bins would require to differentiate between outer and inner vertical edges. I wasn't able to do it quickly and unfortunately I cannot spend more time on this project at the moment.

While figuring out how the workbench is implemented I've added some pseudo classes for easier understanding. There is a chance that the inheritance tree is not entirely correct, but it mostly works.
It's for language server typing annotations only, so obviously not required and can be removed.
I've tried to avoid coupling to freecad stubs since with 1.1 there are native python bindings in FreeCAD.

A screenshot and a couple of prints are attached.
The notches work reasonably well, but for longer parts, thin walls bend and allow for easier sliding.
Thickening the walls helps.
Adding thicker ridges to the bottom of the bin underneath the notches may be another generation option in the future.

The amount of commits is due to poor initial formatter and linter setup.

[greg19]

Can you move the type stubs to a separate PR? This will probably fix most of the failing checks. Then please squash the commits.

[Dooez]

Is an explicit squash necessary?
Squash on merge should achieve a clean main repo history.

[glenn20]

Is an explicit squash necessary? Squash on merge should achieve a clean main repo history.

Squashing commits and rebasing against master makes it much easier for reviewers.