Add auth password for user postgres

[ybak]

without "postgresPassword “property, job "skywalking-skywalking-helm-oap-init" will fail. Cause the other auth properties didn't work for default account "postgres "， and postgresql generated a random password for the default account "postgres "。

[kezhenxu94]

Does the field password not work anymore?

[ybak]

Does the field password not work anymore?

yes, check this out : https://artifacthub.io/packages/helm/bitnami/postgresql/

global.postgresql.auth.postgresPassword	Password for the "postgres" admin user (overrides auth.postgresPassword)	""
global.postgresql.auth.username	Name for a custom user to create (overrides auth.username)	""
global.postgresql.auth.password	Password for the custom user to create (overrides auth.password)	""