ENH: Add escape score etc as colorings

[corneliusroemer]

Add colorings:

• Escape score
• ACE2 score
• Composite score
• Growth advantage modelled by Wenseleer, Gerstung, Murrell models
• Date of 5th (non misdated) sequence or something like this
• Total reversions
• Diff of reversions
• Number of S mutations
• Diff of S mutations
• Key RBD mutations
• Diff of key RBD mutations
  ...

If you have further ideas, feel free to comment

[corneliusroemer]

A lot of the metadata that's suggested here is already available in https://github.com/corneliusroemer/pango-sequences

Just needs to be added to the tree as colorings - although metadata is usually only available for tips, not for internal nodes

In theory one could reconstruct ancestral sequences/internal nodes and derive things like reversions but that may not be worth it.