impl: cll remove items with filter

assignment/src/main/java/appointmentplanner/customlist/api/CustomLinkedList.java

@@ -7,7 +7,9 @@ public interface CustomLinkedList<T> extends Iterable<T> {
 
   void add(T item);
 
-  void remove(T item);
+  T remove(T item);
+
+  CustomLinkedList<T> removeFound(Predicate<T> filter);
 
   void insertAfter(T reference, T item);