Use Tab for jumping to the next lesson/module in the Course Outline in the editor

[merkushin]

Is your feature request related to a problem? Please describe

Using the Tab key is a conventional method of navigation between inputs. However, if we try to use it while editing the Course Outline it doesn't take the expected effect. At the same time, we can notice how the focus is changing on links and buttons somewhere on the page.

Describe the solution you'd like

By tapping the Tab key we jump to the next element in the Course Outline.