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

Conflicts:
- app/controllers/admin/base_controller.rb
  Some refactoring made upstream, no real conflict.
- app/javascript/mastodon/features/compose/components/compose_form.js
  Updated using upstream's code but using maxChars instead of the
  hardcoded length of 500 characters per toot.
- app/javascript/styles/mastodon/components.scss
  Upstream redesigned the onboarding modal. Not sure why we had a
  conflict there.

config/locales/gl.yml

@@ -531,8 +531,6 @@ gl:
     directory: Directorio de perfil
     explanation: Descubra usuarias según o seu interese
     explore_mastodon: Explorar %{title}
-    most_popular: Máis popular
-    most_recently_active: Máis activa recentemente
     people:
       one: "%{count} persoa"
       other: "%{count} persoas"