mol-plugin: refactoring managers

src/examples/basic-wrapper/index.ts

src/examples/proteopedia-wrapper/index.ts

src/mol-plugin-state/manager/animation.ts

src/mol-plugin-state/manager/snapshots.ts

src/mol-plugin-ui/controls.tsx

src/mol-plugin-ui/state/animation.tsx

src/mol-plugin/context.ts

src/mol-plugin/state.ts