Add spectrum plots showing hits with option for macro or zoomed in view

[n-west]

There's some old plotting code in the plot_utils that plots the whole spectrum with all hits.

Add the ability to

• plot a single hit with some sensible spectrum bandwidth
• plot the full coarse channel with all hits
• plot an event with some sensible spectrum bandwidth
• plot all events in a coarse channel

Most of this exists in notebook cells and just needs to be packaged up nicely