A new PSR-14 event is added that allows to modify the event right before
it is persisted within Destination Data One import.
This for example allows to alter dates, prices, etc.
Improve handling of missing end time in dates.
* Add dependency.
* Remove empty tearDown() methods.
* Fix signature of setUp() to be compatible with recent phpunit.
* Temporary fix syntax issues in test files
Relates: #8092