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/pods/probe/exec-liveness.yaml

@@ -0,0 +1,21 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    test: liveness
+  name: liveness-exec
+spec:
+  containers:
+  - name: liveness
+    image: k8s.gcr.io/busybox
+    args:
+    - /bin/sh
+    - -c
+    - touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 600
+    livenessProbe:
+      exec:
+        command:
+        - cat
+        - /tmp/healthy
+      initialDelaySeconds: 5
+      periodSeconds: 5

content/zh-cn/examples/pods/probe/grpc-liveness.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: etcd-with-grpc
+spec:
+  containers:
+  - name: etcd
+    image: k8s.gcr.io/etcd:3.5.1-0
+    command: [ "/usr/local/bin/etcd", "--data-dir",  "/var/lib/etcd", "--listen-client-urls", "http://0.0.0.0:2379", "--advertise-client-urls", "http://127.0.0.1:2379", "--log-level", "debug"]
+    ports:
+    - containerPort: 2379
+    livenessProbe:
+      grpc:
+        port: 2379
+      initialDelaySeconds: 10

content/zh-cn/examples/pods/probe/http-liveness.yaml

@@ -0,0 +1,21 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  labels:
+    test: liveness
+  name: liveness-http
+spec:
+  containers:
+  - name: liveness
+    image: k8s.gcr.io/liveness
+    args:
+    - /server
+    livenessProbe:
+      httpGet:
+        path: /healthz
+        port: 8080
+        httpHeaders:
+        - name: Custom-Header
+          value: Awesome
+      initialDelaySeconds: 3
+      periodSeconds: 3

content/zh-cn/examples/pods/probe/pod-with-http-healthcheck.yaml

@@ -0,0 +1,20 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: pod-with-http-healthcheck
+spec:
+  containers:
+  - name: nginx
+    image: nginx
+    # defines the health checking
+    livenessProbe:
+      # an http probe
+      httpGet:
+        path: /_status/healthz
+        port: 80
+      # length of time to wait for a pod to initialize
+      # after pod startup, before applying health checking
+      initialDelaySeconds: 30
+      timeoutSeconds: 1
+    ports:
+    - containerPort: 80

content/zh-cn/examples/pods/probe/pod-with-tcp-socket-healthcheck.yaml

@@ -0,0 +1,19 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: pod-with-tcp-socket-healthcheck
+spec:
+  containers:
+  - name: redis
+    image: redis
+    # defines the health checking
+    livenessProbe:
+      # a TCP socket probe
+      tcpSocket:
+        port: 6379
+      # length of time to wait for a pod to initialize
+      # after pod startup, before applying health checking
+      initialDelaySeconds: 30
+      timeoutSeconds: 1
+    ports:
+    - containerPort: 6379

content/zh-cn/examples/pods/probe/tcp-liveness-readiness.yaml

@@ -0,0 +1,22 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: goproxy
+  labels:
+    app: goproxy
+spec:
+  containers:
+  - name: goproxy
+    image: k8s.gcr.io/goproxy:0.1
+    ports:
+    - containerPort: 8080
+    readinessProbe:
+      tcpSocket:
+        port: 8080
+      initialDelaySeconds: 5
+      periodSeconds: 10
+    livenessProbe:
+      tcpSocket:
+        port: 8080
+      initialDelaySeconds: 15
+      periodSeconds: 20