OZG-2964 Refactor search related E2E tests

- Remove "elastic" everywhere - make it independ from a specific product
- Remove data from search server before adding Vorgänge
- Adding more dynamic Vorgänge attributes to the search index
- Make _start-e2e-environment.sh_ more robust
- Add _start-e2e-environment.sh_ to stop the Docker container
- Make remaining search related E2E tests work with new search engine