Re-added Wikidata descriptions to search results.

No longer needs separate query to get them! Also now use
index property for ordering.

Note: Will need to route these descriptions to the article
record as soon as dust settles a bit more on the data layer
refactor. Although, just doing a search doesn't create an
article record, so we may not add descriptions to article
records until an article is actually loaded.

Change-Id: I5ebd0be0e2cd1d02f692818a9258fed4762d5f86