Custom configuration for each game (#632)

![image](https://github.com/user-attachments/assets/5dd139b4-2004-4c13-85d1-fc3378382adf)

![image](https://github.com/user-attachments/assets/9bcb8524-a403-428f-9f98-e8c03c75f079

)

Now you can make a separate configuration (independent file) for each
game. All emulator settings are available except for some UI functionality ones. 
The configuration file can be changed and deleted from a separate menu. The
user configuration menu is available through the context menu on a given application.

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Co-authored-by: Evan Husted <greem@greemdev.net>