added ColorScale parameter

src/mol-plugin/ui/controls/parameters.tsx

src/mol-theme/color/chain-id.ts

src/mol-theme/color/cross-link.ts

src/mol-theme/color/element-index.ts

src/mol-theme/color/polymer-id.ts

src/mol-theme/color/polymer-index.ts

src/mol-theme/color/sequence-id.ts

src/mol-theme/color/unit-index.ts

src/mol-util/param-definition.ts