Update pesummary call

I think the call we have to pesummary is a bit outdated. Specifically, the publication plots aren't generated (at least not by default). Also I'm not sure if there's a maximum number of samples for the skymap specified, I've had skymaps being generated for many hours.

@charlie.hoy would you be able to look at how we call pesummary and suggest any updates?

@gregory.ashton what would you think about adding an option to the ini where users can pass their own string of arguments to pesummary? E.g., pesummary_arguments = "--gw --no_ligo_skymap"