[FR] write indexes in a separated file

[farfromrefug]

I am starting to use your library and i must say i really like it.
Now i am thinking about how to improve it.

One great way to improve it, i think, would be to write indexes and actual data in separated files.
That way the initFS would be much faster, right?
Also we could actually store the indexes (k, o, ...) as binary and not JSON, which would significantly decrease the size of the files.

WHat do you think of this? I am will to try and write it myself if you think it can improve the library.

Thanks