Main chnages for kube/cluster-init.sh for multi-node cluster handling

- create the cluster-utils.sh in pkg/kube for a number of functions
- get EdgeNodeClusterStatus from 'zedkube' for cluster status, cluster
  nodeip, cluster prefix, etc
- a background process to monitor the cluster mode changes
- implement cluster mode change logic and operations for change from
  single-node to cluster, or from cluster back to single-node
- save kube /var/lib at single-node first time setup for later use when
  the mode changes back from cluster mode to single node
- display eve-release string for get node OS-IMAGE field

Signed-off-by: Naiming Shen <naiming@zededa.com>

pkg/kube/Dockerfile

@@ -23,6 +23,7 @@ RUN GO111MODULE=on CGO_ENABLED=0 go build -v -ldflags "-s -w" -o /out/usr/bin/ce
 FROM scratch
 COPY --from=build /out/ /
 COPY cluster-init.sh /usr/bin/
+COPY cluster-utils.sh /usr/bin/
 COPY cgconfig.conf /etc
 
 # k3s