Support reading `nex5 ` files with NeuroExplorer

[h-mayorquin]

The current NeuroExplorer can only read the old format and with some limitations. See comments here:

https://github.com/SpikeInterface/spikeinterface/issues/1773#issuecomment-1707859676

We first require support in Neo for the new5 (I am not aware if they added it yet) and then propagate these changes here.

Follow up on this: #1093

And also linking to upstream needs on: https://github.com/catalystneuro/neuroconv/issues/216