Generate the content for the Article placeholder.
If the user gets to a Article Placeholder, generated from an Item, there are two ways of displaying the item's data:
- as a default content page, which isn't editable
- needs to be clearly marked as placeholder
- will show all statements
- the references should be shown, except "imported from" (doesn't make much sense in this case)
- as a extended version, that is editable
- editing of the layout
- editing of the data
We should probably first look into the default version and from there start with an editable version.