Create static ephys phase plot image

[wbwakeman]

As a Brain Knowledge Platform user, I want to see a summary of the electrophysiology of a cell, so that I can immediately understand at a high level the electrophysiology characteristics of the cell.

Summary:
The ephys phase plot is calculable from information that comes out of IPFX. There are start and end of spike indices determined by IPFX. We could either have the phase plot just show the first spike, in which case we just pull out that waveform between the indices, calculate its time derivative, and plot the voltage (x-axis) vs the derivative of voltage (y-axis).

If we want to average spikes, we could still pull out the spikes in the same way and average them (then do the derivative & plotting) - the only slightly tricky part is getting the lengths of all the waveforms the same (but there are options for dealing with that - filling the ends of shorter ones with NaNs, etc.).

Example image and code references courtesy of NathanG:

The function that plots it is here:
https://github.com/AllenInstitute/mouse-met-figures/blob/408585d3769e99252aef4ef0ac074517dc5fa9b7/mouse_met_figs/summary_fig.py#L294

And that function is called around here:
https://github.com/AllenInstitute/mouse-met-figures/blob/408585d3769e99252aef4ef0ac074517dc5fa9b7/mouse_met_figs/summary_fig.py#L524

In my plotting code, it uses an already-processed version of the AP waveform (basically a version that just takes the next 3 ms after the start of the spike).

Track the output image in LIMS.

size?
layout?
labels?
background/transparency?

Tasks:

• asdf

Acceptance criteria:

• asdf