Add appeals (#17364)

* Add appeals

* Add ability to reject appeals and ability to browse pending appeals in admin UI

* Add strikes to account page in settings

* Various fixes and improvements

- Add separate notification setting for appeals, separate from reports
- Fix style of links in report/strike header
- Change approving an appeal to not restore statuses (due to federation complexities)
- Change style of successfully appealed strikes on account settings page
- Change account settings page to only show unappealed or recently appealed strikes

* Change appealed_at to overruled_at

* Fix missing method error

app/mailers/admin_mailer.rb

@@ -15,6 +15,16 @@ class AdminMailer < ApplicationMailer
     end
   end
 
+  def new_appeal(recipient, appeal)
+    @appeal   = appeal
+    @me       = recipient
+    @instance = Rails.configuration.x.local_domain
+
+    locale_for_account(@me) do
+      mail to: @me.user_email, subject: I18n.t('admin_mailer.new_appeal.subject', instance: @instance, username: @appeal.account.username)
+    end
+  end
+
   def new_pending_account(recipient, user)
     @account  = user.account
     @me       = recipient