As CirrusSearch maintainer I want MediaSearch to use a dedicated dataset built from wikidata that does not rely on the existing wikidata search APIs so that I can improve one without impacting the other.

Sub-tickets will be created as needed but the plan is roughly:

• import commons mediainfo dump to hdfs
• spark job that joins commons & wikidata and output a dedicated dataset for concept lookups
• determine the mapping, possibly experimenting with better techniques (not one field per language) to support multiple languages
• custom elasticsearch query to do query expansion&rewrite
• adapt mediasearch and replace the wikidata search API using query expansion
• optional but would be good to have: provide completion for wikidata items using this same dataset instead of using the wikidata completion API

AC:

• The MediaSearch query builder is no longer using the wikidata search API
• A single request is made to elastic