Unify look of all pages.

Now they have a QTabWidget with no tabs as a background.

gui/pages/ModFolderPage.cpp

@@ -38,6 +38,7 @@ ModFolderPage::ModFolderPage(BaseInstance *inst, std::shared_ptr<ModList> mods,
 	: QWidget(parent), ui(new Ui::ModFolderPage)
 {
 	ui->setupUi(this);
+	ui->tabWidget->tabBar()->hide();
 	m_inst = inst;
 	m_mods = mods;
 	m_id = id;