wip, repr provider

src/apps/canvas/structure-view.ts

src/mol-gl/renderer.ts

src/mol-plugin/state/transforms/visuals.ts

src/mol-repr/representation.ts

src/mol-repr/structure/registry.ts

src/mol-repr/structure/representation/ball-and-stick.ts

src/mol-repr/structure/representation/cartoon.ts

src/mol-repr/volume/registry.ts