Allow to use email template
For now the module is using reports of type html (or text). This is great when defining the notification in custom module. But when user wants to define a notification directly in the database, it is complex because the report creation needs some technical details like a internal report name. Also the edition is much simpler. The only drawback is that email template has already a list of reports to attach but we could simply hide the one on notification if an email template is used. This goes in the same simplification direction than #9320.