Major Description
The current docker example directories are all containing their own docker-compose.yaml, docker-config, .env, and sometimes test.sh files.
There are a lot of duplicates, and if there is something new that needs to be set, it is error prone to set it in all the directories.
The aim of this ticket is to organize the common parts into one place, and use the inheritance and dynamic configuration possibilities of docker to have all things written in one place, so that maintainability get easier. On the contrary, it would be a bit harder to understand the things forr the first sight, so documentation needs to be improved as well to guide the reader more on what is happening where.