Authentication should be enabled on Container Apps

### Existing rule

_No response_

### Suggested rule

Authentication should be enabled on Container Apps.

Container Apps provides built-in authentication and authorization features.

Customers can benefit from this, by providing out-of-the-box authentication with federated identity providers, allowing to focus on the rest of the application.

### Pillar

Security

### Additional context

- [Authentication and authorization in Azure Container Apps](https://learn.microsoft.com/azure/container-apps/authentication)
- [Azure deployment reference](https://learn.microsoft.com/azure/templates/microsoft.app/containerapps/authconfigs)