Handling multiple file system types

[GiulioDallaVecchia]

There are a lot of situations where we need to store data with a tiny file system (like SPIFFS) into an internal flash memory mounted directly in a board. There are another situations where with need to read/store ini configuration from an external SD Card.

In that case we need to be able to manage a multiple file system types in the same project.

Could be nice to add the possibility to manage multiple file system types in the same project.

What do you think about?