wip, structure ui tools

src/mol-plugin/skin/base/components/temp.scss

src/mol-plugin/ui/controls.tsx

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

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

src/mol-plugin/ui/structure/overpaint.tsx

src/mol-plugin/ui/structure/representation.tsx

src/mol-plugin/ui/structure/selection.tsx

src/mol-plugin/util/interactivity.ts

src/mol-plugin/util/structure-overpaint-helper.ts

src/mol-plugin/util/structure-representation-helper.ts

src/mol-plugin/util/structure-selection-helper.ts