Track cycles in solution

[valentinsulzer]

Change experiment and solution classes so that solution.cycles is a list of the cycles (e.g. 1 CCCV charge + CC discharge)
See #1176

[jkoeller]

A related functionality that would be nice is the ability to stop a simulation after capacity drops below e.g. 80%. Once the notion of cycle is defined, the discharge capacity for that cycle could be computed.

This is not the sort of thing that would be handled by an Event, correct? Events get evaluated at each time step? Rather, this would be some new if statement with a break evaluated here perhaps?

[valentinsulzer]

Good idea, yes that would be the place to implement it, and it is separate from Event.
Since it is an "event" for the experiment, the 80% cut-off could simply be specified when creating the experiment class.
More generally, we should have "summary" variables for each "cycle" in a solution, which are a function of "cycle number" but not time within each solution, such as "Discharge capacity [A.h]" but also some averaged measure of LAM, LLI, etc.

I think Jack Lonnborn (@lonnbornj ?) has made a start on this issue, but don't know how far he has got

[lonnbornj]

I have implemented the first part of this (definition of cycles by the user on creation of an Experiment), and currently working on extracting the cycles again at around that line in simulation.py. I'll keep the cut-off functionality in mind as I do so.