Feat: support read egg.require from package.json

[whxaxes]

Checklist

• npm test passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

Description of change

• feat: 支持在 package.json 中读取 egg.require，这样在 ts 项目中就不需要在每个 command 中都加 -r，scripts 就可以精简成

{
  "name": "demo-app",
  "egg": {
    "framework": "aliyun-egg",
    "typescript": true,
    "require": [
      "tsconfig-paths/register",
      "egg-ts-helper/register"
    ]
  },
  "scripts": {
    "dev": "egg-bin dev",
    "test": "npm run lint -- --fix && npm run test-local",
    "debug": "egg-bin debug",
    "test-local": "egg-bin test",
    "cov": "egg-bin cov"
  }
}

• fix: 移除对 _[0] 的读取，这个会带来坑，比如当 _[0] 为文件的时候，baseDir 就出错了，再加上文档上本来就没有描述 _[0] ，因此当 bug 进行移除。

[whxaxes]

怎么 travis 不会被触发了 ?

[whxaxes]

这个分支的 ci 不知道为啥没有在 travis 创建成功，新建了个 PR #121