ViewCourseAction: Responsive design
This is a work-in-progress commit. It breaks the "Add student" input text field and changes the EN locales only.
The goal is to have most elements at the same width and shrink with to a (mobile) minimum. The summary and student sections don't really need the toggle feature because they are at the end the page with no content below. The help text was slightly missleading about adding a list of students; the list has to be comma (not space) separated.
Ideally new students could be directly added at the student list rather than having a whole dedicated section. This is not implemente in the current version of this patch.