Add support for user preferences and `kuberc` files

[jacobtomlinson]

Which project are you requesting an enhancement for?

kr8s

What do you need?

Kubernetes <=1.33 store user preferences in a "preferences" key in kubeconfig. As of KEP3104 and Kubernetes 1.34 these preferences can be stored in a kuberc file which makes them cluster agnostic.

These preferences allow you to set the following things:

• aliases - Custom subcommands for kubectl (we probably don't want to support this in kr8s)
• defaults - Default arguments to be applied to all commands (not sure if we want to support this)
• credentialPluginPolicy - Allows users to deny all, alow all, or allow some client-go credential plugins.
• credentialPluginAllowlist - Enables users to specify criteria for trusting binaries to be executed by the client-go credential plugin system.

The most interesting things in here are allowing/denying specific credential plugins. We may want to take these settings into account when calling the exec auth (see #9).