Clean kubefed resources before uninstall

Created by: najib-houcine

Issue

The kubesphere-delete.sh won't propely remove kubefed from the cluster before removing kubesphere , resulting in namespace kube-federation-system hanging in Terminating state.

Cause

Neither the kubefed CRDs or resources are removed prior to deleting the namespace.

Solution

Clean-up kubefed resources before uninstalling the helm chart as well *.kubefed.io crds before completely removing kube-federation-system namespace.

Note: Following the uninstallation method of the kubefed chart described here https://github.com/kubesphere/ks-installer/tree/master/roles/ks-multicluster/files/kubefed/kubefed#uninstalling-the-chart didn't work