Created the SendNothingHandler. It sends no message if the message could not be found

src/main/java/de/gnmyt/autoresponder/handler/SendNothingHandler.java

@@ -0,0 +1,12 @@
+package de.gnmyt.autoresponder.handler;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class SendNothingHandler extends NotFoundHandler {
+
+    @Override
+    public List<String> handleRequest(String sender, String message) {
+        return new ArrayList<>();
+    }
+}