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

Conflicts:
- `.github/dependabot.yml`:
  Updated upstream, we deleted it to not be flooded by Depandabot.
  Kept deleted.
- `Gemfile.lock`:
  Puma updated on both sides, went for the most recent version.
- `app/controllers/api/v1/mutes_controller.rb`:
  Upstream updated the serializer to support timed mutes, while
  glitch-soc added a custom API ages ago to get information that
  is already available elsewhere.
  Dropped the glitch-soc-specific API, went with upstream changes.
- `app/javascript/core/admin.js`:
  Conflict due to changing how assets are loaded. Went with upstream.
- `app/javascript/packs/public.js`:
  Conflict due to changing how assets are loaded. Went with upstream.
- `app/models/mute.rb`:
  🤷
- `app/models/user.rb`:
  New user setting added upstream while we have glitch-soc-specific
  user settings. Added upstream's user setting.
- `config/settings.yml`:
  Upstream added a new user setting close to a user setting we had
  changed the defaults for. Added the new upstream setting.
- `package.json`:
  Upstream dependency updated “too close” to a glitch-soc-specific
  dependency. No real conflict. Updated the dependency.

app/lib/sanitize_config.rb

@@ -18,6 +18,7 @@ class Sanitize
       gopher
       xmpp
       magnet
+      gemini
     ).freeze
 
     CLASS_WHITELIST_TRANSFORMER = lambda do |env|