Invert the role and database creation tasks

[mtheiss]

Describe the bug

Creating a database owned by a new role is impossible, when the role doesn't exist beforehand.

Playbook

Please paste the playbook you are using. (Consider requirements.yml and
optionally the command you've invoked.)

---
  roles:
    - role: robertdebock.postgres
      postgres_databases:
        - name: demo
          owner: demo
      postgres_users:
        - name: demo
          password: demo
          db: demo
---
- name: robertdebock.postgres
  version: 3.2.2

Output

TASK [robertdebock.postgres : Create postgres database] ***********************************************************************************************************************************
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: psycopg2.errors.UndefinedObject: role "demo" does not exist
failed: [decgn-pr-mbb-bart] (item=demo) => {"ansible_loop_var": "item", "changed": false, "item": {"name": "demo", "owner": "demo"}, "msg": "Database query failed: role \"demo\" does not exist\n"}

Environment

• Control node OS: Debian 12.1
• Control node Ansible version: ansible [core 2.14.3]
• Managed node OS: Ubuntu bookworm/sid

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