zh-trans: add some _index.md files (#11683)

* zh-trans: add some _index.md files

* Update _index.md

content/zh/docs/setup/custom-cloud/_index.md

@@ -0,0 +1,11 @@
+---
+title: 定制的云解决方案
+weight: 50
+---
+
+<!--
+---
+title: Custom Cloud Solutions
+weight: 50
+---
+-->

content/zh/docs/setup/on-premises-vm/_index.md

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+---
+title: 本地部署的虚拟机（On-Premises VMs）
+weight: 60
+---
+
+<!--
+---
+title: On-Premises VMs
+weight: 60
+---
+-->

content/zh/docs/setup/release/_index.md

@@ -0,0 +1,11 @@
+---
+title: "下载 Kubernetes"
+weight: 20
+---
+
+<!--
+---
+title: "Downloading Kubernetes"
+weight: 20
+---
+-->