docs: add chinese and english readme link and fix slides link (#4025)

README.md

@@ -1,5 +1,7 @@
 <img src="https://raw.githubusercontent.com/apolloconfig/apollo/master/doc/images/logo/logo-simple.png" alt="apollo-logo" width="40%">
 
+English | [中文](https://www.apolloconfig.com/#/zh/README)
+
 # Apollo - A reliable configuration management system
 
 [![Build Status](https://github.com/apolloconfig/apollo/workflows/build/badge.svg)](https://github.com/apolloconfig/apollo/actions)
@@ -104,9 +106,9 @@ Demo Environment:
 
 # Presentation
   * [Design and Implementation Details of Apollo](http://www.itdks.com/dakalive/detail/3420)
-    * [Slides](https://myslide.cn/slides/10168)
+    * [Slides](https://github.com/apolloconfig/apollo-community/blob/master/slides/design-and-implementation-of-apollo.pdf)
   * [Configuration Center Makes Microservices Smart](https://2018.qconshanghai.com/presentation/799)
-    * [Slides](https://myslide.cn/slides/10035)
+    * [Slides](https://github.com/apolloconfig/apollo-community/blob/master/slides/configuration-center-makes-microservices-smart.pdf)
 
 # Publication
   * [Design and Implementation Details of Apollo](https://www.infoq.cn/article/open-source-configuration-center-apollo)

docs/en/README.md

@@ -1,5 +1,7 @@
 <img src="https://raw.githubusercontent.com/ctripcorp/apollo/master/doc/images/logo/logo-simple.png" alt="apollo-logo" width="40%">
 
+English | [中文](zh/README)
+
 # Introduction
 
 Apollo is a reliable configuration management system. It can centrally manage the configurations of different applications and different clusters. It is suitable for microservice configuration management scenarios.
@@ -98,9 +100,9 @@ Demo Environment:
 
 # Presentation
 * [Design and Implementation Details of Apollo](http://www.itdks.com/dakalive/detail/3420)
-    * [Slides](https://myslide.cn/slides/10168)
+  * [Slides](https://github.com/apolloconfig/apollo-community/blob/master/slides/design-and-implementation-of-apollo.pdf)
 * [Configuration Center Makes Microservices Smart](https://2018.qconshanghai.com/presentation/799)
-    * [Slides](https://myslide.cn/slides/10035)
+  * [Slides](https://github.com/apolloconfig/apollo-community/blob/master/slides/configuration-center-makes-microservices-smart.pdf)
 
 # Publication
 * [Design and Implementation Details of Apollo](https://www.infoq.cn/article/open-source-configuration-center-apollo)

docs/zh/README.md

@@ -1,5 +1,7 @@
 <img src="https://raw.githubusercontent.com/ctripcorp/apollo/master/doc/images/logo/logo-simple.png" alt="apollo-logo" width="40%">
 
+[English](en/README) | 中文
+
 # Introduction
 
 Apollo（阿波罗）是一款可靠的分布式配置管理中心，诞生于携程框架研发部，能够集中化管理应用不同环境、不同集群的配置，配置修改后能够实时推送到应用端，并且具备规范的权限、流程治理等特性，适用于微服务配置管理场景。
@@ -104,9 +106,9 @@ Java客户端不依赖任何框架，能够运行于所有Java运行时环境，
 
 # Presentation
   * [开源配置中心Apollo的设计与实现](http://www.itdks.com/dakalive/detail/3420)
-    * [Slides](https://myslide.cn/slides/10168)
+    * [Slides](https://github.com/apolloconfig/apollo-community/blob/master/slides/design-and-implementation-of-apollo.pdf)
   * [配置中心，让微服务更『智能』](https://2018.qconshanghai.com/presentation/799)
-    * [Slides](https://myslide.cn/slides/10035)
+    * [Slides](https://github.com/apolloconfig/apollo-community/blob/master/slides/configuration-center-makes-microservices-smart.pdf)
 
 # Publication
   * [开源配置中心Apollo的设计与实现](https://www.infoq.cn/article/open-source-configuration-center-apollo)