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](https://kubernetes.io/docs/reference/config-api/kubeconfig.v1/)
- a [task page](https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/) 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](https://github.com/kubernetes/website/issues/38662), [credential plugins](https://kubernetes.io/docs/reference/access-authn-authz/authentication/#client-go-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