Update Mediavault playbook, refs #32050

ansible/inventories/example-ha/group_vars/mediavault.yml

ansible/inventories/example/group_vars/mediavault.yml

ansible/molecule/default/tests/test_mediavault.py

ansible/playbooks/mediavault/add_backup.yml

ansible/playbooks/mediavault/deploy.yml

ansible/playbooks/mediavault/ressources/add_backup_task.yml

ansible/playbooks/site.yml

ansible/roles/mediavault/defaults/main.yml

ansible/roles/mediavault/handlers/main.yml

ansible/roles/mediavault/meta/main.yml

ansible/roles/mediavault/tasks/mailer.yml

ansible/roles/mediavault/tasks/main.yml

ansible/roles/mediavault/templates/systemd-backup-service.j2

ansible/roles/mediavault/templates/systemd-backup-timer.j2

ansible/roles/mediavault/templates/systemd-mailer-script.j2

ansible/roles/mediavault/templates/systemd-mailer-service.j2