Backup/Restore with disk snaphot (Phase1)

[xgerman]

We need to implement backup/restore for the write region. In particualr:

• Explore CNPG backup: https://github.com/cloudnative-pg/cloudnative-pg/blob/main/docs/src/backup.md and evaluate against barman cloud
• Implement a volume snaphot backup in the write region
• Implement & Test restore of the write region

Note: In this pase we won't support PITR.