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