Adding user to courses at registration

Is your feature request related to a problem? Please describe.
It would simplify/reduce the task of adding new users by being able to add them directly to one/several courses at registration.

Describe the solution you'd like
When adding an user in the backend, it would be very timesaving to have the option adding to courses/sessions.
A simple checkbox or box selection (as already available in the backend) would be handy, but it might be a bit tricky by keeping the rights management in mind.
So this might only be available for admins/instance admins.