Do not load all dates of each event

Most of the time dates are fetched and shown.
They need the event to show info like title.
But they nearly never need further dates, except in detail view.

Turning this property lazy will save a lot of data fetching and mapping
and provides a huge performance impact.

Classes/Domain/Model/Event.php

@@ -131,6 +131,7 @@ class Event extends AbstractEntity
     /**
      * @var ObjectStorage<Date>
      * @Extbase\ORM\Cascade remove
+     * @Extbase\ORM\Lazy
      */
     protected $dates;