[postgresql] Create a chart using a previous backup

[mgrzybek]

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We should be able to restore a previous backup to create a ready-to-use service. For instance, a fresh database is empty and we have to create objects.

Inputs to add:

• an S3 bucket and their credentials

Steps:

1. Create the PVC
2. Start PostgreSQL in recovery mode as a batch
3. Start PostgreSQL as a service