feat: perfect migrate to @vue/cli-service, upgrade vue babel version (#1267)

* feat: perfect migrate to @vue/cli-service, upgrade vue babel version

1. update to @vue/cli-service@3.0.5, @babel/core@7.0.0
2. use vue-cli service replace config file in build/ and config/
3. upgrade vue and babel configuration
4. solve the svg-sprite config problem #980

refs: #932 #1087  #980 #1056

* fix: fix breadcrumb dependency

* fix: fix index template and static assets load with vue-cli 3

* fix: fix import driver.js in guide page

* refactor(mock): mak mock api compatible with both web-view and webpack server

1. 把 Mockjs 功能移到 server 端中间件，同时也兼容前端直接劫持 XHR
2. dev 环境下默认作为 express 中间件通过 webpack server 提供 mock api
3. prod 构建时，默认在前端用 Mockjs 劫持 XHR

benefits:
  - dev 开发调试时能直接看到 XHR 请求，方便调试网络，能和后端对接联调
  - 避开在开发时因为 Mockjs 引起的网络 bug
  - prod 构建时劫持 XHR，保证本项目的 Github Pages preview 能正常显示 (逻辑和 error-log 一样)
  - 前后台使用的 mock 是同一份代码，不会增加维护负担

ref: [#562](https://github.com/PanJiaChen/vue-element-admin/issues/562#issuecomment-378116233)

* update requires the lowest version of node

* add favicon

* fix(TreeTable): fix `Array.prototype.concat` on custom-tree-table page

mock/index.js

@@ -0,0 +1,50 @@
+import Mock from 'mockjs'
+import mocks from './mocks'
+import { param2Obj } from '../src/utils'
+
+const MOCK_API_BASE = '/mock'
+
+export function mockXHR() {
+  // 修复在使用 MockJS 情况下，设置 withCredentials = true，且未被拦截的跨域请求丢失 Cookies 的问题
+  // https://github.com/nuysoft/Mock/issues/300
+  Mock.XHR.prototype.proxy_send = Mock.XHR.prototype.send
+  Mock.XHR.prototype.send = function() {
+    if (this.custom.xhr) {
+      this.custom.xhr.withCredentials = this.withCredentials || false
+    }
+    this.proxy_send(...arguments)
+  }
+
+  function XHR2ExpressReqWrap(respond) {
+    return function(options) {
+      let result = null
+      if (respond instanceof Function) {
+        const { body, type, url } = options
+        // https://expressjs.com/en/4x/api.html#req
+        result = respond({
+          method: type,
+          body: JSON.parse(body),
+          query: param2Obj(url)
+        })
+      } else {
+        result = respond
+      }
+      return Mock.mock(result)
+    }
+  }
+
+  for (const [route, respond] of Object.entries(mocks)) {
+    Mock.mock(new RegExp(`${route}`), XHR2ExpressReqWrap(respond))
+  }
+}
+
+const responseFake = (route, respond) => (
+  {
+    route: new RegExp(`${MOCK_API_BASE}${route}`),
+    response(req, res) {
+      res.json(Mock.mock(respond instanceof Function ? respond(req, res) : respond))
+    }
+  }
+)
+
+export default Object.keys(mocks).map(route => responseFake(route, mocks[route]))