Add summary grid plot of saturating suspensions

This adds an additional plot to the summary page that indicates which suspensions tend to saturate with each other. The 1st suspension to saturate in a lockloss goes on the y-axis, and the 2nd-5th saturating suspensions go on the x-axis. The code only looks at suspensions that saturated before the refined lockloss time and does not allow repeats (that come from UR, UL, LR, LL). Samples for LHO and LLO (using my local cluster data) can be found here:

LHO: https://ldas-jobs.ligo-wa.caltech.edu/~yannick.lecoeuche/events/summary_plots/run/suspension_grid.png

LLO: https://ldas-jobs.ligo-la.caltech.edu/~yannick.lecoeuche/events/summary_plots/run/suspension_grid.png

@jameson.rollins Apologies in advance for the many nested loops used to create the grid array. I had originally set up a nice defaultdict to handle the data, but transferred it to a 2d array for imshow.

Closes #126 (closed), though I imagine this is the beginning of several attempts to group this data by lockloss state, associated tags, etc.