isEnabledForCluster is not respected for kubeObjectHandlers in Extension API

[jansav]

Left-over from #5786, since we decided not to treat this as blocker.

kubeObjectHandlers is way too complicated API for the job that it is doing, so better alternative is to simplify the API.

We should refactor remove and edit menu items to be as any other kubeObjectMenuItem. After that we can just introduce enabled computed for those which utilizes currentKubeObject and checks whether it is removable or editable. By doing that extension have a way to remove them by making kubeObject it introduced non removable or editable.