Add kubeadm-gce-selfhosting job to test SelfHosting feature of kubeadm
Add kubeadm-gce-selfhosting job to test SelfHosting feature of kubeadm

GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid