Easy-to-use port-forward command

Give a command like `banzai cluster p[ort-]f[orward]` where the user can choose interactively a clustert, a namespace, a service/deploymentet/pod and an exposed pod, then optionally open it in a browser.

Start by reading the existing `banzai cluster` command and related Kubernetes command entry points. Define how interactive selection should cover a cluster, namespace, service/deployment/pod, and exposed pod, then verify the command can optionally open the selected endpoint in a browser.

Written by the indexing model from the issue text.