Merge branch 'master' into glitch-soc/master

Conflicts:
- `README.md`:
  We have different README files. Discarded upstream changes.
- `app/views/layouts/admin.html.haml`:
  Conflict due to glitch-soc theming system.
  Adapted upstream changes.
- `app/views/layouts/embedded.html.haml`:
  Conflict due to glitch-soc theming system.
  Adapted upstream changes.
- `yarn.lock`:
  No real conflict, glitch-specific dependency too close to
  an updated one. Adapted upstream change.

app/views/layouts/embedded.html.haml

@@ -10,6 +10,7 @@
     - if storage_host?
       %link{ rel: 'dns-prefetch', href: storage_host }/
 
+    = render_initial_state
     = javascript_pack_tag "locales", integrity: true, crossorigin: 'anonymous'
     - if @theme
       - if @theme[:supported_locales].include? I18n.locale.to_s
@@ -21,3 +22,6 @@
 
   %body.embed
     = yield
+
+    %div{ style: 'display: none'}
+      = render file: Rails.root.join('app', 'javascript', 'images', 'logo_transparent.svg')