Add support for FFat

[jaggil]

Hello,
Thanks for this great job.
My question is regarding the possibility of adding the option for the FFat file system.
The FFat system is the one that Espressif has adopted by default in its development today.
Could you take it into consideration?
You could tell me to implement it myself, but unfortunately I don't have enough knowledge for it.
Thanks in advance
Greetings