ATM MediaSearch consists of
a. data stored in the commonswiki_file index in elastic search
b. a search query that makes use of that data, created by code that lives in the WikibaseMediaInfo extension

The query in b. has a set of boosts tuned by optimising for precision@25 on the set of rated media search results in https://github.com/cormacparle/media-search-signal-test

(We may at some stage change b. to use a learning-to-rank model inside elasticsearch, but this ticket will still be relevant if we do)

Once T299885 is done and we are successfully gathering user feedback on whether a suggested image is a good fit, we'll need to incorporate this into our set of rated media search results in order to continuously improve MediaSearch (and consequently image suggestions)

It won't really be clear how to do that until we've made some progress towards getting all the other pieces in place (see T299781), in the meantime this ticket is a placeholder for that work