Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- `app/lib/feed_manager.rb`:
  Not a real conflict, glitch-soc-only DM-related method
  too close to changed upstream stuff.
  Ported upstream changes.
- `app/services/batched_remove_status_service.rb`:
  Additional logic in glitch-soc to clear DMs from timelines.
  Ported upstream changes and fixed the DM TL clearing logic.
- `app/workers/scheduler/feed_cleanup_scheduler.rb`:
  Additional code in glitch-soc to clear DM timelines.
  Ported upstream changes.

lib/mastodon/version.rb

@@ -17,7 +17,7 @@ module Mastodon
     end
 
     def flags
-      'rc2'
+      'rc3'
     end
 
     def suffix