[Feature]: Developer can `cf login` to a `cf-k8s` foundation

[gcapizzi]

Blockers/Dependencies

• [Feature]: Developer can target a cf-k8s foundation via cf api #10

Background

Our strategy for authenticating the cf CLI is to teach the CLI to understand and apply $KUBECONFIG when talking to cf-k8s foundations.

Here we want to allow users to select which auth-info they want to use from their $KUBECONFIG. We want to do this via a prompt, as part of cf login.

Acceptance Criteria

GIVEN a cf-k8s foundation exists
AND I have some auth-info entries in my $KUBECONFIG
AND I have targeted the foundation with cf api
WHEN I run cf login
THEN I am prompted with a list of the auth-info entry names
AND WHEN I select one of the entries
THEN I see something like this in my $CF_HOME/config.json:

"CFOnK8s": {
    "Enabled": true,
    "AuthInfo": "<the name of the auth-info I have just selected>"
}

Dev Notes

See this comment.