[Feature] Add split_by_group, highpass_spatial_filter, silence_periods, detect_bad_channels

[JoeZiminski]

These are useful preprocessing steps it would be nice to expose, but they require some care.

Highpass Spatial Filter

This requires the recording to be split-by-group (see below).

Split by Group

This is nice as it allows reprocessing to be performed per-group i.e. per-shank. However, I am not currently sure whether all preproecssing should be performed split by group, and how to handle sorting that is split-by-group. Need to ask on Slack. Handling group splitting is straightforward (it returns a dict of recording objects) thanks to SI's nice API.

silence_periods

This led to some problems with other preprocessing steps, is not a key step and is difficult to get the syntax for the arguments (nested list) correct in .yaml, so leaving this for now

detect_bad_channels

This is sensitive to the preproecssing steps and SI usually run after phase shift and filtering, but before CAR. There is a decision to be made as to whether detect_bad_channels is always run after some fixed preproecssing steps (e.g. filtering), or can be dynamically run as some point in a user preprocessing chain depending on input arguments.