with large messages

* PW-818: Fix for Magento 2.3 compatibility

* Set only the isAjax param instead of setting everything again

Accepting notifications for multiple merchant accounts

* PW-515: added fix for Test Notifications

* PW-515: removed old check

* PW-515: added comment

 remove exti and die statements what is not allowed, changed reservered PHP7 name resource to resourceModel following magento conventions and fix to use the right exeption class

* PW-329: Include cron health checks

* An admin message will show up if there is a notification which has not been processed for more than 10 minutes
* Trigger the same check on a notification coming from the Adyen Backoffice

* PW-329: Moved the croncheck into the try/catch clause, minor issues fix.

* PW-329: Moved the cronchecktest so that it is initiated only after the Authentication is done.

PW-243: isDuplicate now checks for the 'original_reference' field, this allows now to process two notifications with the same billing agreement but different payment.

#72 add refunded amount to adyen_order_payment table, fix multiple refunds on same pspreference for split payments, show split payments in overview payment information of the order and add column original_reference to notification table.

fix length field holder name, result URl fix for logger, added some license texts, cleanup code and remove die() statement in a catch statement

Implemented OneClick payment method, seperate log file for notfiications, implemented recurring_contract notification saved into billing agreements

added support for refund and capture, added loggers so it is possible to log to different files(not fully working yet)

implemented authentication for notification, let the notification handler save the date so that timezone is correct, fix that live property is set in the notificaiton table and let the cronjob set notification to done when it is finished

fix notificaitons handler with invoice creation build into and added AdyenAbstract model for abstract configuration