clusterctl support for downloading kubeconfig as context within existing kubeconfig

What would you like to be added (User Story)?

As a developer & operator & user I want to be able to load kubeconfigs into an existing kubeconfig. So that I can have a single kubeconfig as contexts of all my clusters for ease of switching between clusters.

Detailed Description

A kubeconfig flag in "clusterctl get kubconfig" which will create the file or add the kubeconfig as a new context.

Anything else you would like to add?

No response

Label(s) to be applied

/kind feature /area clusterctl