Add "setup --control" option

set -eu

USAGE="Usage:

$0 [-h] [-i INTERFACE] [-d DOMAIN] [-t TOKEN] [--skip-upgrade]

$0 [-h] [-c] [-i INTERFACE] [-d DOMAIN] [-t TOKEN] [--skip-upgrade]

-h|--help       Show this usage and exit

-c|--control    Make the node part of the control-plane, implied if --token is

                not provided.

-i|--interface  Use the first address of INTERFACE as a API advertisement address

-d|--domain     Use DOMAIN as the control plane nodes' shared DNS name

-t|--token      Join a cluster using TOKEN

		-i|--interface) INTERFACE=$2; shift ;;

		-d|--domain) API_DOMAIN=$2; shift ;;

		-t|--token) TOKEN=$2; shift ;;

		-c|--control) CONTROL_PLANE=true ;;

		--skip-upgrade) SKIP_UPGRADE=true ;;

	esac

	shift

	kubeadm_args+=(--pod-network-cidr=10.56.128.0/17)

fi

[[ -v CONTROL_PLANE ]] && kubeadm_args+=(--control-plane)

if [[ -v TOKEN ]]; then

	kubeadm join "${API_DOMAIN}" "$TOKEN" "${kubeadm_args[@]}"

else