Separated completeness and area_type fields
Factored out the proposal and conversation from https://git.gfz-potsdam.de/dynamicexposure/openbuildingmap/database-obmtiles/-/merge_requests/12#note_56310
Factored out the proposal and conversation from https://git.gfz-potsdam.de/dynamicexposure/openbuildingmap/database-obmtiles/-/merge_requests/12#note_56310