Break out TabHolder from Common/UI/ViewGroup.cpp. A few new atlas images

UI/DriverManagerScreen.cpp

@@ -7,7 +7,7 @@
 #include "Core/Config.h"
 #include "Core/System.h"
 
-#include "UI/View.h"
+#include "Common/UI/View.h"
 #include "UI/DriverManagerScreen.h"
 #include "UI/GameSettingsScreen.h"  // for triggerrestart
 #include "UI/OnScreenDisplay.h"
@@ -79,8 +79,6 @@ public:
 	std::string name_;
 };
 
-static constexpr UI::Size ITEM_HEIGHT = 64.f;
-
 DriverChoice::DriverChoice(const std::string &driverName, bool current, UI::LayoutParams *layoutParams) : UI::LinearLayout(UI::ORIENT_VERTICAL, layoutParams), name_(driverName) {
 	using namespace UI;
 	SetSpacing(2.0f);