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

Conflicts:
- `README.md`:
  Upstream updated its README, while we have a completely different one.
  Kept our README.
- `app/controllers/concerns/web_app_controller_concern.rb`:
  Conflict because of glitch-soc's theming system.
  Additionally, glitch-soc has different behavior regarding moved accounts.
  Ported some of the changes, but kept our overall behavior.
- `app/javascript/packs/admin.js`:
  Code changes actually applied to `app/javascript/core/admin.js`

app/models/user.rb

@@ -498,6 +498,7 @@ class User < ApplicationRecord
     BootstrapTimelineWorker.perform_async(account_id)
     ActivityTracker.increment('activity:accounts:local')
     UserMailer.welcome(self).deliver_later
+    TriggerWebhookWorker.perform_async('account.approved', 'Account', account_id)
   end
 
   def prepare_returning_user!