[FR] Support for reading NDS flashcard's SD card when loading from 3DS cia

[malvarenga123]

Is your feature request related to a problem? Please describe.
When you load Godmode9i directly from the 3DS (installed cia), you are able to see the 3DS's SD card (sd:), the flashcard's SD card (fat:), a ramdrive (ram:), a NDS game image (nitro:) and finally the NDS Gamecard which is actually the flashcard.
pkmn-chest, on the other hand, when loaded directly from the 3DS, can only see the 3DS's SD card (sd:) and an empty game in slot-1.

Describe the solution you'd like
Use Godmode9i's logic in pkmn-chest and be able to open sd: and fat:

Describe alternatives you've considered
For now I copy the saves from fat: to sd: using Godmode9i, edit the saves in sd: in pkmn-chest and then copy them back to fat: using Godmode9i again.

Additional context
I was sure I had asked this before but I couldn't find the thread in issues or discussion, that's why I'm posting again.