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

Conflicts:
- `Gemfile.lock`:
  Not a real conflict, just a glitch-soc-only dependency too close to a
  dependency that got updated upstream. Updated as well.
- `app/models/status.rb`:
  Not a real conflict, just a change too close to glitch-soc-changed code
  for optionally showing boosts in public timelines.
  Applied upstream changes.
- `app/views/layouts/application.html.haml`:
  Upstream a new, static CSS file, conflict due to glitch-soc's theming
  system, include the file regardless of the theme.
- `config/initializers/content_security_policy.rb`:
  Upstream dropped 'unsafe-inline' from the 'style-src' directive, but
  both files are very different. Removed 'unsafe-inline' as well.

app/workers/activitypub/delivery_worker.rb

@@ -52,13 +52,9 @@ class ActivityPub::DeliveryWorker
       end
     end
 
-    begin
-      light.with_threshold(STOPLIGHT_FAILURE_THRESHOLD)
-           .with_cool_off_time(STOPLIGHT_COOLDOWN)
-           .run
-    rescue Stoplight::Error::RedLight => e
-      raise e.class, e.message, e.backtrace.first(3)
-    end
+    light.with_threshold(STOPLIGHT_FAILURE_THRESHOLD)
+         .with_cool_off_time(STOPLIGHT_COOLDOWN)
+         .run
   end
 
   def failure_tracker