Make a function to plot the initial OCV before cycle 1 starts for a batch object

[inger-emma]

Is your feature request related to a problem? Please describe.
I need to plot the OCV for many cells before the cycling starts.

Describe the solution you'd like
For example using collectors.BatchSummaryCollector with "columns": ["OCV start"] to plot the start OCV vs. time.

Describe alternatives you've considered
None

Additional context
Nice to have to see that the wetting stage behaves as expected. Also relevant when you do a precharge step to se how that behaves.

[jepegit]

This would be a great enhancement. @inger-emma, do you want to try making it yourself? If so, highly appreciated.

[inger-emma]

@jepegit Yes, unsure about when I will have time, but that was my intention.