export v2: Add config color options to traits
export v2: Add config color options to traits

Traits which are defined in the auspice config JSON 
under `color_options` & appear in the metadata,
should now be exported in the JSON. 

Co-authored-by: Kairsten Fay <15a2d506f2d32236cc3b8c341845404878af0fec@gmail.com>
nextstrain/augur,nextstrain/augur,blab/nextstrain-augur,nextstrain/augur