Add IO tutorial

[h-mayorquin]

OK, I have been very busy but been meaning to this since #3053 and #2958

We should add an IO tutorial were we explain was is the way that we intended for spikeinterface objects to be saved.

This is a discussion post to discuss the details.

My opinion:

• I think it should include a description of the two main functions to save. save_to_binary and save_to_zarr and what kind of arguments it supports.
• A link to the write to nwb how to (on the slow makings by me!).
• Their relationship to provenance, efficiency and a description of the formats. For the folder the structure should include the structure of the folder and for zarr the same equivalent tree (@alejoe91 )

Probably some of this information is distributed in the modules documentation. I will need to fish was already there and just add structure to it.