HackStudio: Start fleshing out the GUI for a GUI designer :^)

I'll be reconstructing parts of the VisualBuilder application here and
then we can retire VisualBuilder entirely once all the functionality
is available in HackStudio.

DevTools/HackStudio/FormEditorWidget.cpp

@@ -0,0 +1,28 @@
+#include "FormEditorWidget.h"
+#include "FormWidget.h"
+#include <LibGUI/GPainter.h>
+
+FormEditorWidget::FormEditorWidget(GWidget* parent)
+    : GScrollableWidget(parent)
+{
+    set_fill_with_background_color(true);
+    set_background_color(Color::White);
+
+    set_frame_shape(FrameShape::Container);
+    set_frame_shadow(FrameShadow::Sunken);
+    set_frame_thickness(2);
+
+    m_form_widget = FormWidget::construct(*this);
+}
+
+FormEditorWidget::~FormEditorWidget()
+{
+}
+
+void FormEditorWidget::paint_event(GPaintEvent& event)
+{
+    GFrame::paint_event(event);
+
+    GPainter painter(*this);
+    painter.add_clip_rect(event.rect());
+}