i realized that since we do no longer validate the presence of required data on loading but only while saving, we don't need to distinguish this situation from the simple no presence situation.

we still need the information of the nullfields to know if a document was saved in a locale with all translated fields set to null (depending on the use case this could make sense so it should work.) i guess it does not hurt to keep the nullfields field with a list of all null fields, in case somebody wants to do a query on those.