Refactor all ActivityPub deliveries to be serialized and signed through one concern (#10966)

app/models/account.rb

@@ -204,6 +204,10 @@ class Account < ApplicationRecord
     end
   end
 
+  def sign?
+    true
+  end
+
   def keypair
     @keypair ||= OpenSSL::PKey::RSA.new(private_key || public_key)
   end

app/models/form/account_batch.rb

@@ -3,6 +3,7 @@
 class Form::AccountBatch
   include ActiveModel::Model
   include Authorization
+  include Payloadable
 
   attr_accessor :account_ids, :action, :current_account
 
@@ -54,13 +55,7 @@ class Form::AccountBatch
 
     return unless follow.account.activitypub?
 
-    json = ActiveModelSerializers::SerializableResource.new(
-      follow,
-      serializer: ActivityPub::RejectFollowSerializer,
-      adapter: ActivityPub::Adapter
-    ).to_json
-
-    ActivityPub::DeliveryWorker.perform_async(json, current_account.id, follow.account.inbox_url)
+    ActivityPub::DeliveryWorker.perform_async(Oj.dump(serialize_payload(follow, ActivityPub::RejectFollowSerializer)), current_account.id, follow.account.inbox_url)
   end
 
   def approve!

app/models/status.rb

@@ -204,6 +204,8 @@ class Status < ApplicationRecord
     public_visibility? || unlisted_visibility?
   end
 
+  alias sign? distributable?
+
   def with_media?
     media_attachments.any?
   end