[STG] blackbox_exporter_servicemonitors: client bastion + init mono configuration

To handle blackbox_exporter_servicemonitors, only one file, containing all configurations, for now :

• blackbox_exporter_servicemonitor
• blackbox_exporter_servicemonitor_client
• blackbox_exporter_servicemonitor_client_bst

But we could easily add others like :

• blackbox_exporter_servicemonitor_infra

• blackbox_exporter_servicemonitor_infra_app_01

• blackbox_exporter_servicemonitor_infra_app_02

• blackbox_exporter_servicemonitor_cloud

• blackbox_exporter_servicemonitor_cloud_app_01

• blackbox_exporter_servicemonitor_cloud_app_02