The left and right arrow keys have not any real advantage / functionality for
the playlist view or sidebar but are used by default for several hotkeys.
So lets allow these as VLC hotkeys (also for audio files).
(cherry picked from commit fc33caea8f87af71454f4aacc0be91c247f21889)
Signed-off-by: David Fuhrmann <david.fuhrmann@googlemail.com>