fix integration tests

citing !9 (comment 1189162)

"The integration tests need a menshen instance running. A public instance would work, too. Original plan was to have an own instance in the CI (CI runs make integration_test wich runs docker-compose up but that's docker in docker). That's the current state."

This issue tracks the progress to make this happen. There's an example how to configure menshen in an integration test: menshen@32a2dc9d

We may need to double check if the runner supports docker-in-docker.