Add information differentiating unique WT hexamers to bc_counts/all_counts/rawCounts

[joephun]

Is your feature request related to a problem? Please describe.
This is largely for the cases where a VCF file is included and looking at MAFs and such.
Need hexamer information for the correct FTM call (wt or some variant indicated in the VCF) in order to construct coverage plots based on the "ontarget" hexamers.
In the current version, it's hard to filter bc_counts/raw_counts/all_counts for barcodes that bind to the correct target. Barcodes that are shared between the variant/wt are labeled the same in the ID column as the region column, making it difficult to filter out wt/variant easily, as the barcodes that are unique to the wt are labeled similarly as to those that are shared.

Describe the solution you'd like

Either something in the ID column/separate column that may differentiate whether a hexamer is a unique WT hexamer or a shared hexamer. I imagine this gets a little difficult if there are many different variants for a given position in a WT region, as there may be several overlapping hexamers at different positions. How is this dealt with currently? Would a hexamer that appears at the base of interest, but is also shared with the WT at another position just show up as two different entries?

Describe alternatives you've considered
I suppose if coverage information/diversity per base is available when molecule_seqs is formed, coverage plots and be constructed relatively simply. However, would still need information about particular hexamers that bind to the made FTM call target, so not sure if this would cover what is needed.

Additional context
Add any other context or screenshots about the feature request here.