💡 Feature request: First-class container registry resource and improved registry support

[davidfowl]

Is there an existing issue for this?

• [x] I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

Better support for existing registries is needed in Aspire. Currently, adding and using container registries is not streamlined, especially when working in both run mode and deploy mode. Authentication with registries (prompting for credentials, managing and saving them) is not first-class, and pushing containers to registries typically requires a compute environment, which is limiting.

Describe the solution you'd like

• Add a first-class container registry resource that can be used in run mode and deploy mode.
• Implement authentication flows (prompt for credentials, save them securely, etc.) for container registries.
• Enable support for pushing containers to the registry without requiring a compute environment.

This would make working with container registries much more seamless and enable more flexible workflows in Aspire.

Additional context

This feature would improve developer experience and deployment flexibility for projects using Aspire and containers. It would also help users who need to authenticate and push containers during local development or CI/CD workflows without specific compute resources. Additional context: requested by @davidfowl.