Ingest more statements when fetching lexemes, etc; add ranks to statements

The additional statements will show up when fetching lexemes, lexeme forms, and lexeme senses.

Every statement will now have a field Z6003K4/rank, with one of the 3 values from Z6040 / Wikidata statement rank.

A few tests will fail until function-schemata!174 (merged) is pulled through. In the meantime, this is complete and reviews are welcome!

(Note: It would be good to know whether the additional statements might cause more occurrences of the timeout described in T377338. I hope to look at this soon.)

Bug: T378044

Closes T378044