that contains PostgreSQL`user` and `password` that the Che server uses to connect to the DB.
When the secret is defined, the `chePostgresUser` and `chePostgresPassword` are ignored.
When the value is omitted or left blank, the one of following scenarios applies:
1. `chePostgresUser` and `chePostgresPassword` are defined, then they will be used to connect to the DB.
2. `chePostgresUser` or `chePostgresPassword` are not defined, then a new secret with the name `postgres-credentials`
will be created with default value of `pgche` for `user` and with an auto-generated value for `password`.
The secret must have `app.kubernetes.io/part-of=che.eclipse.org` label.²