Ladybird: Port over ConsoleWidget from the SerenityOS Browser

While this adds a fair bit of widget code, we're also increasing code
sharing by using the same bits in WebContentClient for interacting with
the JS console.

That said, we should look for more ways to share code here.

Ladybird/WebContentView.h

@@ -25,6 +25,10 @@
 class QTextEdit;
 class QLineEdit;
 
+namespace Ladybird {
+class ConsoleWidget;
+}
+
 namespace WebView {
 class WebContentClient;
 }
@@ -152,11 +156,9 @@ private:
     qreal m_inverse_pixel_scaling_ratio { 1.0 };
     bool m_should_show_line_box_borders { false };
 
-    QPointer<QWidget> m_js_console_widget;
     QPointer<QWidget> m_inspector_widget;
 
-    QTextEdit* m_js_console_output_edit { nullptr };
-    QLineEdit* m_js_console_input_edit { nullptr };
+    Ladybird::ConsoleWidget* m_console_widget { nullptr };
 
     Gfx::IntRect m_viewport_rect;