Implemented the JFX HTML renderer

src/main/java/org/openautonomousconnection/webclient/ui/MainFrame.java

@@ -21,7 +21,7 @@ public final class MainFrame extends BrowserFrame {
     private Tab openTab;
 
     @Getter
-    private DOMContainerPanel domContainerPanel;
+    private final DOMContainerPanel domContainerPanel;
 
     public MainFrame() {
         super(new TabButtonView());
@@ -38,6 +38,7 @@ public final class MainFrame extends BrowserFrame {
 
         this.add(this.topBar, BorderLayout.NORTH);
         this.domContainerPanel = new DOMContainerPanel();
+        this.add(this.domContainerPanel, BorderLayout.CENTER);
     }
 
     private void init() {