chore(postgres): add more comments explaining each section

postgres/app/helmrelease.yaml

@@ -69,9 +69,10 @@ spec:
         options: []
         encoding: UTF8
     backups:
-      # Backups are disabled in this example, but here's an example
-      # on how to configure this cluster to export backups to a S3
-      # bucket hosted on a MinIO server. 
+      # As indicated by the 'enabled' flag, backups are disabled on
+      # this deployment. But the remaining of the block serves as an
+      # example of how to configure this cluster to export backups to
+      # a S3 bucket hosted on a MinIO server.
       # 
       # For more information, refer to the helm chart's values.yaml 
       # or the official documentation at 
@@ -91,10 +92,18 @@ spec:
       secret:
         create: true
       wal:
+        # If exporting to MinIO S3, you may have to disable encryption.
+        # This is how you achieve it
         encryption: ""
       data:
         encryption: ""
       scheduledBackups:
+        # You can give it any name and change the scheduled time to what
+        # fits your strategy. This serves as an example of how to configure
+        # the cluster to export a daily backup to the S3 bucket using
+        # barman object storage. You can also back up volumes instead.
+        # Check the backup documentation to find more information on
+        # which option suits you best.
         - name: daily-minio
           schedule: "@daily"
           backupOwnerReference: self