Switch language name 'zh' to 'zh-cn'

This is the first step to rename 'zh' to 'zh-cn'. There are several reasons why we rename the language name.

- The upstream docsy theme changed the language name, leading to many warnings during site build;
  The side-effect is that the i18n strings are no longer working.
- We believe renaming the language is the right thing to do, because this move can make room for other variants of Chinese language, such as 'zh-tw', 'zh-sg' etc.

There would be several follow-ups to this PR, such as fixing the intra-site links, adding redirects etc.

We will lock up changes to zh/zh-cn pages for the moment, until this one gets in.

This PR is based on commit cdad0a7342.

content/zh-cn/examples/admin/logging/fluentd-sidecar-config.yaml

@@ -0,0 +1,25 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: fluentd-config
+data:
+  fluentd.conf: |
+    <source>
+      type tail
+      format none
+      path /var/log/1.log
+      pos_file /var/log/1.log.pos
+      tag count.format1
+    </source>
+
+    <source>
+      type tail
+      format none
+      path /var/log/2.log
+      pos_file /var/log/2.log.pos
+      tag count.format2
+    </source>
+
+    <match **>
+      type google_cloud
+    </match>

content/zh-cn/examples/admin/logging/two-files-counter-pod-agent-sidecar.yaml

@@ -0,0 +1,39 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: counter
+spec:
+  containers:
+  - name: count
+    image: busybox:1.28
+    args:
+    - /bin/sh
+    - -c
+    - >
+      i=0;
+      while true;
+      do
+        echo "$i: $(date)" >> /var/log/1.log;
+        echo "$(date) INFO $i" >> /var/log/2.log;
+        i=$((i+1));
+        sleep 1;
+      done
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  - name: count-agent
+    image: k8s.gcr.io/fluentd-gcp:1.30
+    env:
+    - name: FLUENTD_ARGS
+      value: -c /etc/fluentd-config/fluentd.conf
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+    - name: config-volume
+      mountPath: /etc/fluentd-config
+  volumes:
+  - name: varlog
+    emptyDir: {}
+  - name: config-volume
+    configMap:
+      name: fluentd-config

content/zh-cn/examples/admin/logging/two-files-counter-pod-streaming-sidecar.yaml

@@ -0,0 +1,38 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: counter
+spec:
+  containers:
+  - name: count
+    image: busybox:1.28
+    args:
+    - /bin/sh
+    - -c
+    - >
+      i=0;
+      while true;
+      do
+        echo "$i: $(date)" >> /var/log/1.log;
+        echo "$(date) INFO $i" >> /var/log/2.log;
+        i=$((i+1));
+        sleep 1;
+      done
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  - name: count-log-1
+    image: busybox:1.28
+    args: [/bin/sh, -c, 'tail -n+1 -F /var/log/1.log']
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  - name: count-log-2
+    image: busybox:1.28
+    args: [/bin/sh, -c, 'tail -n+1 -F /var/log/2.log']
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  volumes:
+  - name: varlog
+    emptyDir: {}

content/zh-cn/examples/admin/logging/two-files-counter-pod.yaml

@@ -0,0 +1,26 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: counter
+spec:
+  containers:
+  - name: count
+    image: busybox:1.28
+    args:
+    - /bin/sh
+    - -c
+    - >
+      i=0;
+      while true;
+      do
+        echo "$i: $(date)" >> /var/log/1.log;
+        echo "$(date) INFO $i" >> /var/log/2.log;
+        i=$((i+1));
+        sleep 1;
+      done
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  volumes:
+  - name: varlog
+    emptyDir: {}