[Build] revert site to webpack config (#3747)

docs/site/mobile/main.js

@@ -0,0 +1,38 @@
+import '../../../src/index.less';
+import Vue from 'vue';
+import VueRouter from 'vue-router';
+import App from './App';
+import routes from '../router';
+import { importAll } from '../utils';
+import '@vant/touch-emulator';
+
+const componentMap = {};
+const context = require.context('../../../src', true, /demo\/index.vue$/);
+
+importAll(componentMap, context);
+
+const router = new VueRouter({
+  mode: 'hash',
+  routes: routes({ mobile: true, componentMap }),
+  scrollBehavior(to, from, savedPosition) {
+    return savedPosition || { x: 0, y: 0 };
+  }
+});
+
+router.afterEach(() => {
+  if (!router.currentRoute.redirectedFrom) {
+    Vue.nextTick(() => window.syncPath());
+  }
+});
+
+window.vueRouter = router;
+
+if (process.env.NODE_ENV !== 'production') {
+  Vue.config.productionTip = false;
+}
+
+new Vue({
+  el: '#app',
+  render: h => h(App),
+  router
+});