Config supports reading multiple kubeconfig files with scattered information

[manusa]

Description

Part of #6516

After implementing #6551 and #6556 there's still a missing feature to be able to refresh and persist the information provided in those files it's scattered on different files.

Considering a scenario where a user has the kubeconfig information fragmented:

• The current-context is defined in a file
• The context is defined in a different file
• The cluster referenced in the context is defined in a different file
• The user referenced in the context is defined in a different file

The client and its Config management procedures need to be able to identify where each information was extracted from in case it needs to be updated or persisted.