* [PW-1942]: Admin notifications overview for adyen_notification table

* [PW-1942]: Added notifications overview link to cron information message

* [PW-1942]: Added notifications overview link to cron information message

* [PW-1942]: Adjusted columns, filters and formatting on notifications overview
Moved PSP search URL function to helper since it is now being used in multiple places

* [PW-1942]: Changed virtualType classname to avoid conflicts with Notifications Collection

* [PW-1942]: Implemented getPspReferenceSearchUrl() from library

* [PW-1942]: Unit testing

* [PW-1942]: Applying recommended changes:
* Renamed XML files to adyen_notifications_overview
* Applied PSR2 code styling to CronMessage.php
* Updated Copyright year
* Early return and replaced switch with if and default value in NotificationColumn.php. Also, docs state that success can only be true/false so got rid of third CSS class
* Moved getPspReferenceSearchUrl() method from PHP Lib to Data helper, and added if/else to receive liveEnvironment from notification record instead of receiving test/live string

* [PW-1942]: Code styling

* [PW-1942]: Applying recommended changes:
* Inverted live/test if check
* Removed unnecessary constructor
Co-authored-by: cyattilakiss <42297201+cyattilakiss@users.noreply.github.com>