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/audit/audit-policy.yaml

@@ -0,0 +1,68 @@
+apiVersion: audit.k8s.io/v1 # This is required.
+kind: Policy
+# Don't generate audit events for all requests in RequestReceived stage.
+omitStages:
+  - "RequestReceived"
+rules:
+  # Log pod changes at RequestResponse level
+  - level: RequestResponse
+    resources:
+    - group: ""
+      # Resource "pods" doesn't match requests to any subresource of pods,
+      # which is consistent with the RBAC policy.
+      resources: ["pods"]
+  # Log "pods/log", "pods/status" at Metadata level
+  - level: Metadata
+    resources:
+    - group: ""
+      resources: ["pods/log", "pods/status"]
+
+  # Don't log requests to a configmap called "controller-leader"
+  - level: None
+    resources:
+    - group: ""
+      resources: ["configmaps"]
+      resourceNames: ["controller-leader"]
+
+  # Don't log watch requests by the "system:kube-proxy" on endpoints or services
+  - level: None
+    users: ["system:kube-proxy"]
+    verbs: ["watch"]
+    resources:
+    - group: "" # core API group
+      resources: ["endpoints", "services"]
+
+  # Don't log authenticated requests to certain non-resource URL paths.
+  - level: None
+    userGroups: ["system:authenticated"]
+    nonResourceURLs:
+    - "/api*" # Wildcard matching.
+    - "/version"
+
+  # Log the request body of configmap changes in kube-system.
+  - level: Request
+    resources:
+    - group: "" # core API group
+      resources: ["configmaps"]
+    # This rule only applies to resources in the "kube-system" namespace.
+    # The empty string "" can be used to select non-namespaced resources.
+    namespaces: ["kube-system"]
+
+  # Log configmap and secret changes in all other namespaces at the Metadata level.
+  - level: Metadata
+    resources:
+    - group: "" # core API group
+      resources: ["secrets", "configmaps"]
+
+  # Log all other resources in core and extensions at the Request level.
+  - level: Request
+    resources:
+    - group: "" # core API group
+    - group: "extensions" # Version of group should NOT be included.
+
+  # A catch-all rule to log all other requests at the Metadata level.
+  - level: Metadata
+    # Long-running requests like watches that fall under this rule will not
+    # generate an audit event in RequestReceived.
+    omitStages:
+      - "RequestReceived"