Update Screen system

Added FuelScreen (Working buttons)
Added SellScreen (Nothing working)

Game/Gui/Screens/ScreenManager.h

@@ -0,0 +1,31 @@
+#pragma once
+#include "../Screen.h"
+
+
+
+class ScreenManager
+{
+public:
+	static ScreenManager* GetInstance();
+
+	void OpenScreen(Screen* screen);
+	void CloseScreen();
+
+	Screen* GetCurrentScreen() { return m_currentScreen; }	
+	
+	static ScreenManager* m_pInstance;
+
+
+	static Screen* Fuel;
+	static Screen* SellScreen;
+private:
+	ScreenManager() = default;
+
+	void InitializeScreens();
+	
+	bool m_IsScreenOpen{ false };
+	Screen* m_currentScreen;
+
+	bool m_AreScreensInitialized{ false };
+	
+};