Story: As an OpenShift administrator I want to use a CLI tool to discover what OpenShift releases and Operator catalogs exists so that I can select the most appropriate one to mirror for a disconnected OpenShift cluster.

Background: It is not possible today for a user to know upfront which OCP versions are available for installation and mirroring. Because this information is missing it's hard for the user to reason about what specific version of OCP release payload and Operator catalogs should be mirrored in order to supply a reproducible mirror.

Prior work:

• oc adm mirror CLI proposed in disconnected mirroring improvement proposal (link)
• fake README.md for new disconnected mirroring process (link)

Acceptance criteria:

• the CLI has the ability to query a public Red Hat API to discover what OCP releases are available for mirroring
• the CLI has the ability to query a public Red Hat API to discover what OCP Operator Catalogs are available for mirroring
• if required, the CLI will expect registry credentials in the default credentials location of podman and docker ($XDG_RUNTIME_DIR/containers/auth.json om RHEL/CentOS/Fedora)
• if required, the CLI will probe registries before doing any work by attempting to login using the existing credentials and fall back to user input of username and password if this fails, the CLI will error out if any of the interactively provided credentials fail to authenticate