Ensure public access is disabled for Azure PostgreSQL Server

Allowing unrestricted, public access to cloud services could open an application up to external attack. Disallowing this access is typically considered best practice.

In Azure Console -

1. Open the Azure Portal and go to Azure Database for PostgreSQL servers.
2. Choose the PostgreSQL server you wish to edit.
3. Under Networking, set Connectivity method to Public access (allowed IP addresses).
4. Select save.

In Terraform -

1. In the azurerm_postgresql_configuration resource, set public_network_access_enabled to false.

References:
https://learn.microsoft.com/en-us/azure/postgresql/flexible-server/quickstart-create-server-portal
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/postgresql_server