增加apidoc模块生成api文档，不过接口描述我只写了一个

[hhdem]

1. 使用apidoc模块生成api静态文档省去维护的工作
2. 去掉原有的api接口
3. 静态文件apidoc的生成目录在public/apidoc
4. 增加public/apidoc到gitignore中

[mention-bot]

@hhdem, thanks for your PR! By analyzing the history of the files in this pull request, we identified @alsotang, @greenkeeperio-bot and @fengmk2 to be potential reviewers.

[codecov-io]

Codecov Report

Merging #939 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #939      +/-   ##
==========================================
+ Coverage   87.74%   87.77%   +0.02%     
==========================================
  Files          53       53              
  Lines        2334     2331       -3     
  Branches      342      342              
==========================================
- Hits         2048     2046       -2     
+ Misses        286      285       -1

Impacted Files	Coverage Δ
web_router.js	94.8% <ø> (-0.07%)	⬇️
api/v1/topic.js	89.92% <ø> (ø)	⬆️
controllers/static.js	100% <ø> (+8.33%)	⬆️

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