Add support for single-shank probes

[bparks13]

Instead of assuming that all Neuropixels 2.0 probes are quad-shank probes. add in support for single-shank probes. This should mirror the Onix1 library, in that the user has the option to choose which probe is connected, and the visualization / configuration should update accordingly.

Since we know the probe part number as reported by the hardware when connecting, is it worth compiling a list of probe numbers that are currently implemented so that we don't run into any issues in the future where someone chooses the wrong probe type?