Separate sync as its own stream in SpikeGLXRawIO

[h-mayorquin]

Same as #1668. Should come after it.

[samuelgarcia]

I am OK with this.

Maybe we should have load_sync_channel=None being the semantic not trigerring warning before the removal of this option.

Do we need a spikeinterface change or not ?

[h-mayorquin]

Maybe we should have load_sync_channel=None being the semantic not trigerring warning before the removal of this option.

So you want an option that loads the sync channels but does not throw the warning? As in, the users know that it will be deprecated but they want to keep using it without warning until we do. Is that correct?

Do we need a spikeinterface change or not ?

I think for this case just a deprecation warning as there are always at least two streams in SpikeGLX.

[zm711]

One question but then this is good by me?

for me I don't see the need of the None mechanism. People have been using this for a while so if they say True we should warn them that this is changing and the default is False so no warning.

[samuelgarcia]

Everything is ok for me.
No worry about the none stuff.

[h-mayorquin]

Thanks for the review.