[bitnami/postgresql] Don't put postgresql-postgres-password in secret when not needed (#5635)

* Don't put postgresql-postgres-password in secret when not needed

When only using the "postgres" user, the secret gets updated every helm upgrade with a
random string. When using with argocd (and maybe other gitops tools) there are always
changes until you put a dummy value into postgresqlPostgresPassword.

Use the same conditional as in statefulset.yaml:
~~~
{{- if not (eq (include "postgresql.username" .) "postgres")  }}
  # (..)
- name: POSTGRES_POSTGRES_PASSWORD
  valueFrom:
    secretKeyRef:
      name: {{ template "postgresql.secretName" . }}
      key: postgresql-postgres-password
{{- end }}
{{- end }}
~~~

* Use same conditional for readreplicas

In PR #4380 we forgot to also change the 2nd statefulset for the readreplicas

bitnami/postgresql/templates/secrets.yaml

@@ -11,7 +11,9 @@ metadata:
   namespace: {{ .Release.Namespace }}
 type: Opaque
 data:
+  {{- if not (eq (include "postgresql.username" .) "postgres")  }}
   postgresql-postgres-password: {{ include "postgresql.postgres.password" . | b64enc | quote }}
+  {{- end }}
   postgresql-password: {{ include "postgresql.password" . | b64enc | quote }}
   {{- if .Values.replication.enabled }}
   postgresql-replication-password: {{ include "postgresql.replication.password" . | b64enc | quote }}