* Add announcements

Fix #11006

* Add reactions to announcements

* Add admin UI for announcements

* Add unit tests

* Fix issues

- Add `with_dismissed` param to announcements API
- Fix end date not being formatted when time range is given
- Fix announcement delete causing reactions to send streaming updates
- Fix announcements container growing too wide and mascot too small
- Fix `all_day` being settable when no time range is given
- Change text "Update" to "Announcement"

* Fix scheduler unpublishing announcements before they are due

* Fix filter params not being passed to announcements filter

* Delete trends_controller.rb

* Update routes.rb

* Update trending_tags.rb

* Update index.js

* Update index.js

* Update search_results.js

* Update async-components.js

* Update index.js

* Delete trends.js

* Delete trends.js

* Delete trends_container.js

* Delete trends.js

* Update search_results.js

* Update search_results_container.js

* Allow collapsing trends, responsively hide trends

* Add trends column