Clean zh/docs directory for dangling YAML files (#17341)

There are many YAML manifests sneaking into the `zh/docs/` directory.
These files should go to the `zh/examples` directory instead. Having
these "garbage" files (not referenced anywhere) is creating confusion
for the release meister when merging branches. For example, some YAML
files found in the 'master' branch are no longer there in the
release-1.16 branch. It is tedious, if possible at all, to solve all
this kind of conflicts during a rebase.

The PR cleanses the zh/docs directory for all dangling YAML files.

content/zh/docs/tasks/inject-data-application/define-environment-variable-container.md

@@ -26,12 +26,12 @@ content_template: templates/task
 本示例中，将创建一个只包含单个容器的Pod。Pod的配置文件中设置环境变量的名称为`DEMO_GREETING`，
 其值为`"Hello from the environment"`。下面是Pod的配置文件内容:
 
-{{< code file="envars.yaml" >}}
+{{< codenew file="pods/inject/envars.yaml" >}}
 
 1. 基于YAML文件创建一个Pod:
 
     ```shell
-    kubectl create -f https://k8s.io/docs/tasks/inject-data-application/envars.yaml
+    kubectl apply -f https://k8s.io/examples/pods/inject/envars.yaml
     ```
 
 1. 获取一下当前正在运行的Pods信息: