Use esp-idf vfs

[annejan]

This branch by @rnplus seems like a good way to bolt the esp-idf vfs under micropython in stead of its default vfs.

[Spritetm]

Erm... all the code in there is dummy'ed out, is that intentional?

[annejan]

Sorry for lack of intro from irc .. this is not yet ready code
Just a start . .
So yes, it seems it is intentional 😉

[basvs]

Reviewing my own code…

mount(), umount() and mkfs() are not supported (although mount() is used as trigger to mount the filesystem on /) → this is all intentional

open() is a bit verbose when the open fails.
we might want to lower this one day..

[basvs]

previous comments mentioned stubs. there shouldn't be any stubs anymore.