Upgrade PGO to 5.7.0; Add option to disable backups

[sunu]

Related to #181 (comment)

Disabling backups is only an option if using PGO >= 5.7.0

Along with disabling the backups, we can also set some Postgres settings to keep the storage consumed by WAL files in check. Here's an example:

postgrescluster:
  backupEnabled: false
  instances:
  - name: eoapi
    replicas: 1
    dataVolumeClaimSpec:
      accessModes:
      - "ReadWriteOnce"
      resources:
        requests:
          storage: "5Gi"
          cpu: "0.5"
          memory: "512Mi"
  patroni:
    dynamicConfiguration:
      postgresql:
        parameters:
          max_wal_size: "64MB"
          min_wal_size: "32MB"
          wal_keep_size: "64MB"
          checkpoint_timeout: "1min"

[ividito]

Should this default to false until we can recommend a more robust default configuration for pgBackrest?

[sunu]

@ividito Yeah, that was my first instinct too. But if the default is false, we could break existing setups where someone upgrades eoapi without also updating PGO. The bigger risk is that users with a working backup config might upgrade to the latest chart and miss this new flag -- suddenly their working backup mechanism will be silently ignored.

[pantierra]

I think at the moment we can still be a bit aggressive on introducing "breaking changes". I would put is as false and make sure in the next release notes we mention this new flag.

[sunu]

Alright, happy to make the change if we think breaking changes are ok for now.

[sunu]

@ividito @pantierra - updated the PR. Can I get another round of review before we merge please?

[pantierra]

👍