* [PW-2199]: New can_cancel config value that avoids all order cancellations

* [PW-2199]: Removed can_cancel check from files not related to notification processing

* [PW-2199]: Renamed config value for clarity

* [PW-2199]: Fixing adyenHelper object

* [PW-2199]: Checking config value before changing order status to NEW

* Newline at the end of Config.php

* [PW-2199]: Removing dependency on AbstractHelper