benchmarked MATLAB ApRES processing code

[jkingslake]

As discussed (https://github.com/orgs/autonomous-phase-sensitive-radar/discussions/1#discussioncomment-12011419), there is value in developing and hosting a matlab-based ApRES processing code for use by the community

There is a suite of matlab scripts and functions that many people are familiar with (it includes fmcw_plot.m), which we should probably adopt.

@KeithNicholls , you mentioned you have code that you wouldnt mind preparing for this. Is it similar (or perhaps the same) as this one you sent us a few year ago: https://github.com/ldeo-glaciology/phase-sensitive-radar-processing/tree/main/code/ApRES_Utils_Nicholls_250221
Or have things developed since then?