add custom RGB settings

[KanikaNahata]

Problem

Custom RGB settings for transitions, circles, nodes do not work. + Would it be possible to add custom RGB settings for the map and labels as well?

Spread link: https://view.spreadviz.org/?output=ddf9ff80-334a-475d-8cdd-901925a32877/dcfb953a-9a35-4bb6-bc15-2643036b57b0.json&maps=CN,KP,BD,RU,NP,BT,MN

customRGB_720p.mov

[fbielejec]

we don't have the designs for that, marking as V2 for future enhancements