This is one followup of MDL-27925

Now it's possible to specify where navigation nodes are added and it's considered a good usability approach to have all the activity-related ones together on top (under the standard "edit settings" one).

Also it would be great to do this for all modules once we support separators in navigation (MDL-27909) so everything will look really better.

As reference, this commit is the implementation performed for the quiz module: bc502c16

Ciao