Merge pull request #188 from iqb-berlin/group-monitor-active

src/app/app-root/test-starter/test-starter.component.ts

src/app/group-monitor/backend.service.ts

src/app/group-monitor/group-monitor.component.ts

src/app/shared/websocket-backend.service.spec.ts

src/app/shared/websocket-backend.service.ts

src/app/shared/websocket.service.spec.ts

src/app/shared/websocket.service.ts

src/app/test-controller/command.service.ts

src/app/test-controller/focus.service.ts

src/app/test-controller/test-controller.component.html

src/app/test-controller/test-controller.component.ts

src/app/test-controller/test-controller.interfaces.ts

src/app/test-controller/test-controller.module.ts

src/app/test-controller/test-controller.service.ts

src/app/util/uuid.ts

src/environments/environment.dev.ts