[Feature]: Option to select SD card storage for offline maps

[MeshMapperBot]

Platform: Other

Description:
I downloaded the latest 1.3.0 beta 1779073780 and see the offline maps option but don't see an option to save to external SD storage. Does your code auto select the external storage and not use the internal storage? If so amazing!

Discord: https://discord.com/channels/1463383723327356992/1473328116511543399/1516392756241629194

Submitted by: beachmiles (Discord)