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/suspend_account_service.rb

@@ -13,6 +13,7 @@ class SuspendAccountService < BaseService
 
   def purge_content
     @account.statuses.reorder(nil).find_each do |status|
+      # This federates out deletes to previous followers
       RemoveStatusService.new.call(status)
     end
 
@@ -29,9 +30,7 @@ class SuspendAccountService < BaseService
     @account.display_name = ''
     @account.note         = ''
     @account.avatar.destroy
-    @account.avatar.clear
     @account.header.destroy
-    @account.header.clear
     @account.save!
   end