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/services/appeal_service.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class AppealService < BaseService
+  def call(strike, text)
+    @strike = strike
+    @text   = text
+
+    create_appeal!
+    notify_staff!
+
+    @appeal
+  end
+
+  private
+
+  def create_appeal!
+    @appeal = @strike.create_appeal!(
+      text: @text,
+      account: @strike.target_account
+    )
+  end
+
+  def notify_staff!
+    User.staff.includes(:account).each do |u|
+      AdminMailer.new_appeal(u.account, @appeal).deliver_later if u.allows_appeal_emails?
+    end
+  end
+end