added flag to frontend

...ster/masterthesis/Testgenerator/rest/dto/BPMNFlowDTO.java

...r/masterthesis/Testgenerator/rest/dto/FlowElementDTO.java

...hesis/Testgenerator/rest/service/flow/FlowController.java

...src/app/components/bpmn-diagram/bpmn-diagram.component.ts

...nerator-web/src/app/components/flows/flows.component.html

...generator-web/src/app/components/flows/flows.component.ts

...generator-web/src/app/components/test/test.component.html

...stgenerator-web/src/app/components/test/test.component.ts

...web/testgenerator-web/src/app/models/bpmn-flow-element.ts

...nerator-web/testgenerator-web/src/app/models/bpmn-flow.ts

testgenerator-web/testgenerator-web/src/index.html