Linked visualisation of Foldseek 3Di MSAs with corresponding 3D structures

Using Nick Matze's 3diTree as an example:
 https://github.com/nmatzke/3diphy/tree/main/jalview

Goal(s):
(1) map alignment colors onto a structure even if the AA codes don't match - assuming 1:1 correspondence
(2) Provide Martin's 3Di-gecos.jc a default.
(3) provide a way to switch between and/or link amino acid and 3Di sequences - stretch goal