chart color pallet

[tomwayson]

Add a new top level styles to the definition w/ the first prop being colors: string[].

For cedar-amcharts this will override the chart's default colors property which is set int the theme:

cedar/packages/cedar-amcharts/src/themes/calcite.js

Line 11 in 48ff5b0

colors: ['#0079c1', '#e4d154', '#5a9359', '#de2900', '#9081bc', '#005e95', '#338033', '#d9bf2b', '#a57946', '#ab3c16', '#7461a8'],

NOTE: that the array of colors is the pallet of colors available to the chart, and is used to supply the default colors for the series but does not have to be 1:1 - there can (and usually should) be more colors in this pallet than there are series.

This seems to be common to most chart libraries:
https://docs.amcharts.com/3/javascriptcharts/AmSerialChart#colors
https://www.amcharts.com/docs/v4/reference/serialchart/#colors_property
https://ecomfe.github.io/echarts-doc/public/en/option.html#color
https://c3js.org/samples/options_color.html
https://naver.github.io/billboard.js/release/latest/doc/Options.html#.color

The beginning of this work has been done in #382. This issue is to capture just the colors property. The background/text colors will be handled in #435 at a later time.