access to private images in cloud providers' registries

[lluan444]

Currently Orion works for public images and images on docker registry. A new capability is needed to support access to private images on cloud providers' private registries.

Orion leverages go-containerregistry module for registry access. According to its README, a NewKeychainFromHelper needs to be implemented to handle cloud provider specific authentication and authorization. Two example helpers are mentioned for Amazon ECR and Azure ACR.

Suggest the following two actions:

1. Implement a NewKeychainFromHelper for ibmcloud. Get details on ibmcloud authentication and registry APIs.
2. Incorporate available KeychainFromHelpers, and implement the use of appropriate KeychainFromHelper based on target registry (image url).