Use environment variables in docker-compose

[erbesharat]

🐛 Bug Report

Some of the variables like MONITORER_ADMIN_PASSWORD and MONITORER_ADMIN_USER in docker-compose are currently constants which should be changed to fetch their data from env variables.

To Reproduce

Steps to reproduce the behavior: Not needed.

Expected behavior

Read all of the important variables from the environment variables.

Environment

Not needed.

[revolunet]

You could use a docker-compose.override.yml to override these variables