Mutualize minio tenants configuration

Summary

Creating a Minio tenant requires to provide complex configuration.

Two minio tenants are created for now in values.yaml for logging and monitoring. Another one is created to test backup with a dedicated values file (https://gitlab.com/sylva-projects/sylva-elements/ci-tooling/ci-deployment-values/current/backup.yam)

Introducing a new unit_templates may simplify creating new tenants.