This implementation obviously lacks a lot of things, and there are a lot of TODOs. However, there are already a lot of questions I'd rather get answered soon, so I figured it's much easier to do the implementation in steps.
I wrote down all breaking changes, suggested changes, and new additions with comments (TODO and Note).
In a follow-up PR I will:
Add the remaining/missing models
Make the workflows handle all interactions between the different models/modules
Add integration tests