Fix host metadata on GKE

[CharlyF]

What does this PR do?

The agent's status output contains the metadata exposed by the GCE metadata endpoint.
This contains the startup script for containerd as well as the kubeconfig.

This makes the status output very large with irrelevant data.

  Hostnames
  =========
    host_aliases: [gke-x-hcw0 gke-x-default-pool]
[...]
      google-compute-enable-pcid:true
      kube-labels:beta.kubernetes.io/fluentd-ds-ready=true,cloud.google.com/gke-nodepool=default-pool,cloud.google.com/gke-os-distribution=cos,runtime=containerd
      cluster-location:europe-west1
      containerd-configure-sh:#!/bin/bash

# This is a copy of https://raw.githubusercontent.com/containerd/cri/release/1.11/cluster/gce/configure.sh

set -o xtrace
set -o errexit
set -o nounset
set -o pipefail

# CONTAINERD_HOME is the directory for containerd.
CONTAINERD_HOME="/home/containerd"
[...]
mount --bind -o ro "${CONTAINERD_HOME}" "${CONTAINERD_HOME}"
      cluster-uid:xxx
      kubelet-config:apiVersion: kubelet.config.k8s.io/v1beta1
authentication:
  anonymous:
    enabled: false
  webhook:
[...]

[albertvaka]

Is this good to be merged @CharlyF ?