Timeseries of domain averaged mean and stdev or box whisker plots of domain averaged fields

- [ ] Generate box whisker plots for 2D fields to investigate the data range against forecast range
- [ ] Then extend the capability to create a timeseries of box whisker plots against forecast range. Alternatively use a line for the median and shading for percentiles. This will be useful to look at differences between UM and LFRic.
- [ ] include option to plot the timeseries of box whisker plots from two different simulations in the same figure
- [ ] @jfrost-mo does the cycling over model simulation happen at cylc level or via templating in the recipe? I assume the first. using $model_run in the recipe?
- [ ] requires completion of ticket #453 first