Implement utility function to generate "independent events plot" for an ROI from its crosstalk data file

[danielsf]

The learning mFISH team would like to be able to visualize the events that occur in an ROI both in its detection plane and the plane that is coupled to it through crosstalk.

@nataliaorlova has prototype code to generate this plot. The decrosstalk module already stores the data needed to generate these plots in automatically-generated HDF5 files. In discussion with Natlia, it was decided that we should implement a utility function to read in one of those HDF5 files and then generate the necessary plots for a specified ROI on demand.

That function almost certainly should not live in this repository (the learning mFISH team will want to incorporate it into the QC notebooks). I am just opening this ticket here since this is where the decrosstalk code lives.

[nataliaorlova]

Here is the link to the prototype code:
https://github.com/AllenInstitute/mesoscope_ica/blob/0b316aefea63c0fea69ae201863098c428b3dee5/mesoscope_ica/plotting.py#L993

And here is the notebook, visualizing the plot:
https://github.com/AllenInstitute/mesoscope_ica/blob/main/notebooks/Plot_ROI_with_events.ipynb