Freyja-plot

Fixed
* freyjaPlotter methods now correctly compare samples for which one group is missing samples of the same grouping (name/date)

Added
* can now bin low-abundance lineage into their superlineages in `FreyjaPlotter.plotLineages`

Added
* plots to summarize lineage detection when abundance values aren't relevent
* boxplot capability
* can now return the data behind some figures using `return_df`

Added
* can now plot lineage proportions over vs time
* can now stack subplots, one for each scheme (with shared x-axis)

Added
* superlineages can optionally be based on data from cov-lineages
* date info can be added in for plotting lineage appearance

Changed
* lineage plot now has lineages labeled
* general reorgaizing
Added
* Can now combine multiple lineage plots as subplots via FreyjaPlotter.combineLineagePlots()
* Can now view lineage appearance over time via FreyjaPlotter.plotAppearance()
* FreyjaPlotter.colorMap updates each time new lineages are plotted and keeps colors the same across plots