[FR] Display scale of PMT's flash as a size, not a color. Add option to overlay hypothesis and flash in vis tool

[bear-is-asleep]

Is your feature request related to a problem? Please describe.
I mainly would like a way to visualize hypotheses and flashes overlayed for debugging.

Describe the solution you'd like
Above

Describe alternatives you've considered
One could display the hypothesis behind the existing flashes with a similar color pattern for amount of PE. This may be easier.

Additional context
I implemented something like this in a PMT visualization tool called PAD where the time of the PMT's flash is the color, and the size is the PE.