Make file attachment on MediaAttachment optional (#1865)

Create MediaAttachment but without actual file download when domain is blocked with reject_media set to true
Clean up old media files when creating a new domain block with reject_media set to true
Return remote_url in media attachments API if local file is not present
Undo domain block action in admin UI
Ability to enable reject_media from admin UI

app/services/unblock_domain_service.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class UnblockDomainService < BaseService
+  def call(domain_block, retroactive)
+    if retroactive
+      if domain_block.silence?
+        Account.where(domain: domain_block.domain).update_all(silenced: false)
+      else
+        Account.where(domain: domain_block.domain).update_all(suspended: false)
+      end
+    end
+
+    domain_block.destroy
+  end
+end