[Feature] Allow backing up of data from individual NSO titles

[wfowler1]

Currently you can dump the entire save data for an NSO title. For example, the Nintendo 64 NSO can be dumped, and the individual games' files will all be in there. But it'd be great if you could just dump the save file for one game, like GoldenEye or B-K. This would drastically simplify things when you're backing up or restoring save data for more than one game at a time.

[wfowler1]

I should clarify, currently you can interact with the individual files in the save data, but the names of the folders are all pretty unhelpful, just stuff like "N-4868_e". And the file manager part of the app is currently a bit clunky to use. I think it'd be great to have something a bit more fleshed out for these titles so you know what game you're actually backing up.