Move the Base.save to Sorting.save() and Recording.save()

[samuelgarcia]

This PR refactors the BaseExtractor.save() function to unify and simplify the implementation:

• Remove the _save() function and deprecate save_to_memory, save_to_folder, save_to_zarr: the save() function is now the only entry point for saving
• The BaseRecording and BaseSorting route the save to the main backend formats, which have a write_* statich method to handle all the write logic (e.g., BinaryFolderRecording.write_recording())
• Remove the folder_metadata concept, used previously to save the probe object and not needed since Use ProbeGroup object instead of contact_vector property and set_probe/probegroup from select_channels_with_probe/probegroup #4465 (now the probegroup is dumped to dictionary as extra metadata)
• Centralize saving and loading of properties and annotations to folder
• Deprecate BaseSnippets object, since it's not an intended use case we want to suppor in the future

In addition to these changes, this PR also integrates #4689, which improves the handling of times in several ways:

• it adds time info to the dict only when it has been modified in memory
• it changes the write_binary function to also write timestamps in chunks when available
• it modifies FrameSliceRecoridng and BasePreprocessor to lazily handleand return timestamps from parent, instead od making a full copy

[alejoe91]

@samuelgarcia fixed some bugs in preprocessing, but there are more. Do you want me to fix it?

[alejoe91]

@samuelgarcia ported changes from #4689 (timestamps handling + removing metadata_folder) and cleaned up code and docs.

One main question: in #4689 , I added an extra _in_reduce mechanism to the to_dict/_extra_metadata_to_dict stack. This was only set to True by the __reduce__, and propagated times kwargs only in this case.

Here I propose a modified version: if the user "messes" with timestamps, this is propagated to dict no matter what. Note that:

• this is needed when saving in parallel (timestamps need to be saved!)
• the final si_folder.json will NOT have this information, since it sets include_extra_metadate=False (added also include_annotations/include_properties to False)

Let me know what you think!

[chrishalcrow]

Would be nice to save the main_ids somewhere near here

[alejoe91]

let's do that.

[alejoe91]

done in 443f80a

[alejoe91]

@samuelgarcia @chrishalcrow all done! Ready to merge on my end.