Introduce the game variables struct (#338)

Co-authored-by: emiyl <me@emiyl.com>

* Introduce the game variables struct

* Fix clang format

* Move game variables into their own file

include/splash_screen.h

@@ -7,6 +7,8 @@
 #ifndef SPLASH_SCREEN_H
 #define SPLASH_SCREEN_H
 
+#include "game.h"
+
 #include <tonc.h>
 
 /** @name Splash screen timing variables
@@ -23,16 +25,16 @@
 /**
  * @brief Initialize the splash screen by printing the splash screen text.
  */
-void splash_screen_on_init(void);
+void splash_screen_on_init(GameVariables* vars);
 
 /**
  * @brief Update splash screen timers and print the remaining time accordingly.
  */
-void splash_screen_on_update(void);
+void splash_screen_on_update(GameVariables* vars);
 
 /**
  * @brief Exit the splash screen
  */
-void splash_screen_on_exit(void);
+void splash_screen_on_exit(GameVariables* vars);
 
 #endif // SPLASH_SCREEN_H