Add ColorTheme.palette support

src/examples/basic-wrapper/custom-theme.ts

src/examples/basic-wrapper/index.html

src/examples/basic-wrapper/index.ts

src/mol-geo/geometry/color-data.ts

src/mol-gl/renderable/schema.ts

src/mol-gl/shader/chunks/assign-color-varying.glsl.ts

src/mol-gl/shader/chunks/assign-material-color.glsl.ts

src/mol-gl/shader/chunks/color-frag-params.glsl.ts

src/mol-gl/shader/chunks/color-vert-params.glsl.ts

src/mol-theme/color.ts