Co-authored-by: Jean Boussier <jean.boussier@gmail.com>

* Add trending statuses

* Fix dangling items with stale scores in localized sets

* Various fixes and improvements

- Change approve_all/reject_all to approve_accounts/reject_accounts
- Change Trends::Query methods to not mutate the original query
- Change Trends::Query#skip to offset
- Change follow recommendations to be refreshed in a transaction

* Add tests for trending statuses filtering behaviour

* Fix not applying filtering scope in controller

Express follow_recommendations in terms of account_summaries rather than
accounts, integrate filters that are unconditionally used, and materialize
the resulting view.

This should result in the bulk of the computation being performed only once
instead of **once per recommendation language**.