Color control make-over

[wlhunt]

Several things to do for making over the palette and background color controls.

-unify (to the extent reasonable) the controls across all models
-add achromatic/grayscale or monochromatic palettes to all models possible
-potentially add vtk.js palettes to 3D model options
-potentially split the background color control off, to be independent from the palette choice

a few links:
https://clauswilke.com/dataviz/color-pitfalls.html
https://github.com/d3/d3-scale-chromatic#sequential-single-hue
https://uxdesign.cc/zoning-in-on-grayscale-for-data-visualization-b1c7da77580d

[alexsielicki]

Current progress from me is unification of controls across CCA and PS models. Still need to extend this to other models.

@Spurs20 added grayscale palettes.