Install mc client into master containers

Background:
We can leverage buildbot MasterShellCommand:
https://docs.buildbot.net/latest/manual/configuration/steps/master_shell_command.html

In order to run commands local to the master. (e.g. in container).

The general idea is that we need a way to create / delete buckets from a minIO instance.
We remove the need to install mc client on every worker machine (container, non-latent), by installing it on the master container and let the master handle the bucket creation (via MasterShellCommand step)

Purpose of this task
Update master container to have the mc client installed.
We will control the creation of an alias (https://min.io/docs/minio/linux/reference/minio-mc/mc-alias-set.html#id8) directly from the startup script.

To distinguish buildbot DEV from PROD, we make use of the .env files to expose minIO configuration options (WG IP of the instance, port) to every master container.

The start up script will then call the mc client to create the configuration on container start-up via docker-compose.

Notes:
For Production, until we migrate it to containers, we can install the MC client on hz-bbm1 and configure it there (masters are running as services, on the host).