Improved Flash Cart Support

• Rework how the default player state is initialized to allow the game to run on flash carts without SRAM
• Add the option to hold SELECT when first initializing the player state to unlock all skills/upgrades, as a shortcut for players without SRAM
• Remove redundant bank switching writes which cause problem when run from a flash cart which mimics MBC5 (EMS or cheap repros)
• Ensure OAM is fully initialized before enabling objects for the boot logo effect