HackStudio: Project templates and New Project dialog

This commit adds a simple project template system to HackStudio,
as well as a pretty New Project dialog, inspired by early VS.NET
and MS Office.

Base/res/devel/templates/cpp-gui/main.cpp

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <LibGUI/Application.h>
+#include <LibGUI/Window.h>
+#include <LibGUI/Button.h>
+#include <LibGUI/MessageBox.h>
+
+int main(int argc, char** argv)
+{
+    auto app = GUI::Application::construct(argc, argv);
+
+    auto window = GUI::Window::construct();
+    window->set_title("Hello friends!");
+    window->resize(200, 100);
+
+    auto button = GUI::Button::construct();
+    button->set_text("Click me!");
+    button->on_click = [&](auto) {
+        GUI::MessageBox::show(window, "Hello friends!", ":^)");
+    };
+
+    window->set_main_widget(button);
+
+    window->show();
+
+    return app->exec();
+}