The keyboard navigation with MovePageUp/Down and MoveEnd did not honor
disabled cells in all cases which lead to inconsistencies in the
navigation (esp. since MoveHome does honor them correctly).
Therefore make sure that all four move operations work consistent by
refactoring the code to use common functions.
Fixes: QTBUG-72400
Change-Id: I63fa3b626510d21c66f4f9b2b1bfb3261728ecaf
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Luca Beldi <v.ronin@yahoo.it>
Reviewed-by: Samuel Gaist <samuel.gaist@idiap.ch>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>