feat(jui): (re-)add transitional screens

Adds a new MessageScreen class to display custom messages and restores areas where ReceivingLevelScreen was used

Minecraft.Client/UI/Screens/MessageScreen.h

@@ -0,0 +1,27 @@
+#pragma once
+#include "../Screen.h"
+
+// 4jcraft addition
+
+class MessageScreen : public Screen {
+private:
+    std::wstring message;
+
+public:
+    MessageScreen(const std::wstring& message);
+
+protected:
+    using Screen::keyPressed;
+
+    virtual void keyPressed(char eventCharacter, int eventKey);
+
+public:
+    virtual void init();
+    virtual void tick();
+
+protected:
+    virtual void buttonClicked(Button* button);
+
+public:
+    virtual void render(int xm, int ym, float a);
+};