Document upgrade path #1111
Description
The current document editor is not so great, it lacks features and is a bit buggy at times.
We already have a nice markdown editor that can do more than the current document editor. We might be better of making a new Document class that only has a markdown field and a title and use the markdown editor instead.
One important thing to keep in mind is that we probably want to move over to some kind of y.js compatible system in the future, Tiptap (our markdown editor) already has supports that (although I'm not sure if it is available in the FOSS version).
Switching to md only will also make adding a y.js representation trivial in the future as we can just add it another property
In order to not break existing documents we should make a new class and migrate old documents to the new version when they are opened, this is probably easier done on the client.
Should we make this automatic or present the user with a button to update and disable editing until the document has been updated or should we do it automatically?