There is no specific date, so we can't provide one I am afraid
That feature, is not among features which our users are asking much, and we have to optimize our development based on the most asked and wanted features
On top of that, this feature gave us and our users a lot of grief in the past because some of the users just couldn't understand that you can't include complex and dynamic modules, which required lots of external JS code to work properly. For such users, it was better not to have such feature to be honest
As I said, we will probably implement this but we can't provide a date when this will happen
Thank you for understanding!