app: allow more arrow key navigation
The various ListViews (inclusing e.g. in the global drawer or the device page) can already be navigated with the arrow keys, but it is not possible to move between the individual parts of the app (like going from the global drawer to the device page) cannot, and the plugins that are not solely list views also cannot. This makes keyboard navigation overly reliant on the tab key.
This change implements arrow key navigation between different parts of the app and on all plugins and individual plugin settings pages.
Split from !769 (merged)