Add toggle to switch between Pango and Nextclade nomenclature

[AdvancedCodingMonkey]

• Allow users to flip between showing the Nextstrain name ("23I") and the Pango name ("BA.2.86") across the website - ideally some kind of toggle at the top (or that moves with scroll) so they could turn this on/off easily anywhere and menus/plots would adjust (not necessary for page text or tables to adjust - I think). These are linked in clusters.py
  related to Support well-known variant labels, such as QB.1  #366
  [feature request] Add pango names to Per Country page #313
  Pango & common names #161

[AdvancedCodingMonkey]

Questions for refinement:

• There can be multiple pango lineages, which to use?
• Can alt_display_name be used?
• Where to place toggle?
• Home page:
  • Should variants links update?
• Variants page:
  • Should variants links update?
  • Should the variant urls update?
  • Should we update the individual variants' text?
  • Plot headers need to update
• Should we add something to the FAQ?
• per country page:
  • menu and plot headers should update
  • should filter urls update?
• per variant page:
  • menu and plot headers should update
  • should filter urls update?
• cases page:
  • menu and plot headers should update
  • should filter urls update?
• shared mutations page: should table header update? should the text update?
• acknowledgements: should anything update here?

[AdvancedCodingMonkey]

Further refinement:

• dealing with multiple pango lineages
  • it is just that one clade
  • not really a chance this happens again
  • concatenating the string or finding a solution just for this one clade is fine
• can one use alt_display_name
  • in principle yes, the oldest variants need an update though
• overall strategy
  • variant urls should update and be persistent
  • links to variant pages and page content should update
• add something to the FAQ
• filter urls
  • if the switch state is persisted between reloads, should be ok to not have it represented in the url
  • the variant version in the url is probably overkill
• shared mutations
  • instead of listing both at the same time in the header, update on switch
• acknowledgements
  • only if it is very very little work