Implement RDF export for items and RDF dumps (Turtle only for now)
+ Add compound values support
Use the data with https://www.wikidata.org/wiki/Special:EntityData/Q30.ttl?flavor=full
Flavors: simple, long, full, dump
By default displays the same data as before
Issues: T53795, T50141, T50143, T46580
Change-Id: I51334df5b09bb46fc6e46cbfb56b4b5248335f7e