Also send DnD events through the event filter interface

src/EventFilterInterface.h

@@ -14,6 +14,7 @@
 #include <memory>
 
 class QMouseEvent;
+class QEvent;
 
 namespace KDDockWidgets {
 
@@ -62,6 +63,12 @@ public:
     {
         return false;
     }
+
+    /// @brief Override to handle drag enter, drag leave, drag move and drop events
+    virtual bool onDnDEvent(View *, QEvent *)
+    {
+        return false;
+    }
 };
 
 }