Upgraded dm4-wikidata for DeepaMehta 4.4

Changes:
- WDEntitities of type=property now have re-enabled navigation to involved "items" enabled again.
  Given a property, one can navigate to all (imported) items which "Claims" make use of this property.
  This kind of "bonus feature" was formerly de-activated due to (#672).
- Never download JSON-dumps from /wikidatawiki, use-dump is just functional with existing dumps.
- All topics imported via dumps are associated with the "Wikidata" Workspace automatically.
- More clear exception handling for development