search
This commit is a subset of
https://invent.kde.org/plasma/plasma-mobile/-/merge_requests/694 to add
keyboard navigation to the app drawer.
Pressing the arrow keys while in the app drawer will allow you to
navigate between the apps and the search bar, and going up will exit the
app drawer. Escape/Back is also supported for unfocusing the search bar
and exiting the view.
This also fixes an issue in the keyboard navigation on the search screen
where it wouldn't close when there are no search results.
