### What problem were solved in this pull request?

Problem:
当前生成的github pages不太整洁方便，可以优化一下

### What is changed and how it works?
改用mdbook生成文档，并整理文档目录，调整链接

### What problem were solved in this pull request?

Issue Number: close #89 close #154 

Problem:
how_to_build 文档中描述的编译内容缺少了benchmark，并且步骤过于繁琐。

### What is changed and how it works?
使用build.sh为基础描述构建文档。

### Other information

* 简化git submodule操作