Add "color" option type

[mwestphal]

Is your feature request related to a problem? Please describe.
See #1570

F3D support many option with different option types, it would be beneficial to support a new "color" option type instead of relying on double vector. A color should obviously be stored in a double_vector of size 3.

Describe the solution you'd like

• Add it to types.h with the correct API
• Add a naive parse/format methods to options_tools.h.in
• Use it for at least one option in options.json
• Add testing in TestSDKOptions*

[salfakir]

Thanks for creating this issue