Improvements to Matomo/Piwik setups

1. Backup System

As part of BC/DR, we need a strategy and awareness of the backup/restore processes and timelines. Since OKD is to be used to deploy both apps, we can leverage the automatic backup system ( https://paas.docs.cern.ch/3._Storage/persistent-storage/#data-backup-and-restore) and have a cronjob DB dumping to the filesystem.

This would mean the DB backup lifetime would be the same as the one of the backups provided by OKD.

Currently DBoD provides 1month automatic backups.

2. Deployments instead of DeploymentConfigs

Not very urgent, but DeploymentConfigs are discontinued and they won't get any improvements. A nice to-do would be to move to Deployments for future proofing, as we can then use the latest features of the Kubernetes resource.

DeploymentConfigs currently have secrets written directly instead of using secret resources. To be reviewed if this is the correct approach.

3. Have some Monitoring/Alerting

As part of keeping the infrastructure up and running as expected, we should alerted in case of any disruption.