Qt-Advanced-Docking-System 关闭、禁止拖动、最大化按钮等设置

实现效果：

ads::CDockWidget* pDockWidget1 = new ads::CDockWidget("页面1");
    pDockWidget1->setFeature(ads::CDockWidget::DockWidgetClosable, false);
    pDockWidget1->setFeature(ads::CDockWidget::DockWidgetMovable, false);
    pDockWidget1->setFeature(ads::CDockWidget::DockWidgetFloatable, false);
    m_pDockManger->addDockWidget(ads::LeftDockWidgetArea, pDockWidget1);

    ads::CDockWidget* pDockWidget2 = new ads::CDockWidget("页面2");
    pDockWidget2->setFeature(ads::CDockWidget::DefaultDockWidgetFeatures, false);
    m_pDockManger->addDockWidget(ads::TopDockWidgetArea, pDockWidget2, pDockWidget1->dockAreaWidget());