Remove environment declaration in Dockerfiles
Some variables are declared with the env command and then passed as program arguments.
This behaviour is not compatible with the ability to override these variables through docker compose. In other words, these variables are set statically and cannot be overridden.
As the containers are supposed to be started through a composition, at least for the connection with the database.
We generalise the fact that environment variables are defined in docker compositions and thus avoid any prevalence conflicts in the way spring loads its variables