Add bookmarks (#7107)

* Add backend support for bookmarks

Bookmarks behave like favourites, except they aren't shared with other
users and do not have an associated counter.

* Add spec for bookmark endpoints

* Add front-end support for bookmarks

* Introduce OAuth scopes for bookmarks

* Add bookmarks to archive takeout

* Fix migration

* Coding style fixes

* Fix rebase issue

* Update bookmarked_statuses to latest UI changes

* Update bookmark actions to properly reflect status changes in state

* Add bookmarks item to single-column layout

* Make active bookmarks red

app/javascript/mastodon/features/ui/components/columns_area.js

@@ -21,6 +21,7 @@ import {
   HashtagTimeline,
   DirectTimeline,
   FavouritedStatuses,
+  BookmarkedStatuses,
   ListTimeline,
   Directory,
 } from '../../ui/util/async-components';
@@ -40,6 +41,7 @@ const componentMap = {
   'HASHTAG': HashtagTimeline,
   'DIRECT': DirectTimeline,
   'FAVOURITES': FavouritedStatuses,
+  'BOOKMARKS': BookmarkedStatuses,
   'LIST': ListTimeline,
   'DIRECTORY': Directory,
 };