Special Users can no longer be deleted (PRONTO-5010, ADT-4501)

Updated the application so that BC-User and Service_User can no longer be deleted from the account admin in the user interface, command line, or Webservice call.

This corrects an issue that allowed users to accidentally delete these users, causing additional issues for those customers. Now, only Ops users can delete BC-User and Service_User users. Additionally, this corrects an issue where orphaned spaces could not be deleted after a space ownership change when the owner was a Service_User and should not have been deleted.