Add a task page for setting up kubeconfig

This is an umbrella issue

What would you like to be added Add a new task page that explains how to put a kubeconfig in place for accessing a cluster.

Why is this needed People might set up a PC to authenticate to a cluster that they did not deploy, and would like to learn how.

Comments We already have:

• a reference page
• a task page for when you want to access more than one cluster

but we don't have a task page for setting up kubeconfig when you just want to access a single cluster.

We should try to merge a basic task page first, but leave this issue open until that task is thorough and covers details such as impersonation, credential plugins, and kuberc (experimental - see https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/3104-introduce-kuberc/README.md).

/sig cli /language en /kind feature