[Doc] Add English version of serving/ and java/andriod/. (#963)

* 第一次提交

* 补充一处漏翻译

* deleted:    docs/en/quantize.md

* Update one translation

* Update en version

* Update one translation in code

* Standardize one writing

* Standardize one writing

* Update some en version

* Fix a grammer problem

* Update en version for api/vision result

* Merge branch 'develop' of https://github.com/charl-u/FastDeploy into develop

* Checkout the link in README in vision_results/ to the en documents

* Modify a title

* Add link to serving/docs/

* Finish translation of demo.md

* Update english version of serving/docs/

* Update title of readme

* Update some links

* Modify a title

* Update some links

* Update en version of java android README

* Modify some titles

* Modify some titles

* Modify some titles

docs/README_CN.md

@@ -1,4 +1,4 @@
-[English](README_EN.md) | 简体中文
+[English](README.md) | 简体中文
 
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