Special case for sequences with the pango lineage "Unassigned"

[matthuska]

Recombinant sequences are currently a bit difficult for the software that we use to assign lineages to our SARS-CoV-2 sequences. In some cases, lots of these sequences are assigned the lineage "Unassigned." For vocal, they look like very worrisome sequences, because the background of them being a known VOC (or recombinant of several VOCs) is not taken into account. Sequences can also be legitimately unassigned though, perhaps when they are very different from all known sequences.

Because of this, we would like the Unassigned sequences to be displayed separately and treated specially compared to all other sequences with proper pango lineages. They shouldn't be removed, but they should probably just be shown in a separate part of the final report.