Support creating Wikidata entries when no matching QIDs are found

[diegodlh]

If no QID is found for an item by the Wikidata.getQID, it should be offered to create a new entity in Wikidata. To reduce the probability of creating a duplicate entry, both PID (i.e., DOI/ISBN) AND title (#32) queries should have been tried for an item before offering to create a new entry.

[diegodlh]

An additional difficulty around creating new entities is how to match authors (P50) to Wikidata entities, instead of simply adding author name strings (P2093). OpenRefine's reconciliation may be used for this (as well as for retrieving QIDs for items without a PID #32).

In the meantime, instead of automatically creating new entities with wikibase-edit, the plugin may output QuickStatements instructions, so the user would take care of not creating duplicate entities, and of disambiguating authors.

See #55