Improved title screen implementation and added quit button

[hyperbx]

• The NEW GAME and CONTINUE options (will later refer to as "save options") no longer appear if there is no save data.
• Fixed the PRESS START text not playing an outro animation before transitioning to the save options.
• Fixed the save options not playing an outro animation before transitioning to the main menu.
• Fixed Disable Title Input Delay not affecting the save options.
• Replaced the "Exit the game." confirmation prompt when backing out of the main menu with a message that makes more sense.
• Implemented Game_PlaySound for playing CSB audio.
• Implemented '06-style message windows in ImGui, used in the installer wizard and when pressing the B button at the title screen for confirmation to exit the game.