Change ComputeSpikeLocations to use only peak_sign

[ecobost]

Fixes #4320.

Instead of receiving spike_retriever_kwargs (which was not used anyway), receive peak_sign (mirroring ComputeSpikeAmplitudes). Previous default behavior and capabilities will not change (as peak_sign was the only parameter actually used from spike_retriever_kwargs).

Code will change from

analyzer.compute('spike_locations', spike_retriver_kwargs={'peak_sign': 'both'}) # previous version
analyzer.compute('spike_locations', peak_sign='both') # new version

[ecobost]

Forgot to change references to spike_retriever_kwargs in other code/docs/test.

I found there is only one place where it was used:

spikeinterface/src/spikeinterface/benchmark/benchmark_peak_localization.py

Lines 27 to 30 in 5b2e738

	if not self.channel_from_template:
	self.params["spike_retriver_kwargs"] = {"channel_from_template": False}
	else:
	## TODO

As said in #4320, this didn't actually have any effect (cause spike_retriever_kwargs was not passed to SpikeRetriever()), so I commented this code out.I think spike_locations.py is cleaner/easier-to-understand receiving only peak_sign as argument but if you think the use case in benchmark_peak_localization.py warrants the extra complexity, let me know and I'll revert the changes (and make sure spike_retriever_kwargs is forwarded to the SpikeRetriever).

[samuelgarcia]

This was very important for our benchmark. Lets keep it!
We need the peak channel to be estimated for each peak to take in account the variability.
@yger

[samuelgarcia]

Thank you for this.

We need to be ver very carfull when changing parameters in extension because then when we reload an old analyzer from disck from previous version this will lead to bugs because the params are inconsistent.

In case we change parameters we need to ensure a backward compatibitility using th _handle_backward_compatibility_on_load() method. Also we try to change to often parameters in extension as less as we can for this reason.

In this particular I think we should keep the previous signature with no change and only ensure that this parameters is propagated correctly.

What do you think ?