Create registry default database for new installations

What does this MR do?

Create registry default database

With this change we will allow creating a new registry database with a default username when postgres.install is set to true

This will allow new installations to be ready to enable the registry metadata database.

A new registry-database-password secret has been added to the shared-secrets. This new secret will be used as the registry database password for the database name.

Related issues

Related to Provide the container registry DB by default fo... (#5931 - closed).

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