[#77745832] Searchers see fewer duplicate/similar images in results

- Initial prototype around the concept of sets or events or "albums" with a top photo in each album, ranked by the score of each of those top photos.
[#77745832] Searchers see fewer duplicate/similar images in results

- Added album detector to do basic set detection on photos
- Search now picks most relevant photo from an album instead of showing all potential matches
- Installed sidekiq-failures to track job failures in Sidekiq dashboard
- Fixed copy/paste error in README
- Strip machine readable tags like vision:* and extra title/desc whitespace from Flickr photos before indexing
[#78785104] Fix image search pagination

- This is a stopgap fix until we figure out what changes we want to make to the API w/r/t the "total" field, as we don't have an inexpensive way of determining the total number of buckets. https://github.com/elasticsearch/elasticsearch/issues/4915
[#77745832] Searchers see fewer duplicate/similar images in results

- Improve test coverage