init CardDeckController to use fxml

src/main/java/de/hsfulda/onses/controllers/CardDeckController.java

@@ -1,4 +1,17 @@
 package de.hsfulda.onses.controllers;
 
-public class CardDeckController {
+import de.hsfulda.onses.Main;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+
+import java.io.IOException;
+import java.util.Objects;
+
+public class CardDeckController implements Controller {
+    @Override
+    public Parent render() throws IOException {
+        final Parent parent = FXMLLoader.load(Objects.requireNonNull(Main.class.getResource("views/cardDeck.fxml")));
+
+        return parent;
+    }
 }