Add OEGameCoreOptions for multi-system options and required bios/system files per core

Options:
OEGameCoreHasGlitches - Compatibility and graphics issues; core is WIP. Shows warning at core launch.
OEGameCoreRequiresFiles - Needs bios or system files. Use OERequiredFiles array of dictionaries.
OEGameCoreSaveStatesNotSupported - Save states are not supported. Disables save UI in HUD.
OEGameCoreSupportsCheatCode - Cheat codes are supported. Enables cheat UI in HUD.