POS: Added a parameter to modify barcode activate behaviour

Parameter CONFIRM_QTY_ON_BARCODE_ACTIVATE was added, it can change how a
activation signal on barcode entry behaves. If its set to true, activation on barcode
shall transfer focus to quantity entry. It will maintain its previous behaviour
otherwise.

Change-Id: I76ceec2ff05897a30b6ce4a464269e264145afe6