feature：代码初始化。

src/plugins/index.js

@@ -0,0 +1,18 @@
+import tab from './tab'
+import auth from './auth'
+import cache from './cache'
+import modal from './modal'
+import download from './download'
+
+export default function installPlugins(app) {
+  // 页签操作
+  app.config.globalProperties.$tab = tab
+  // 认证对象
+  app.config.globalProperties.$auth = auth
+  // 缓存对象
+  app.config.globalProperties.$cache = cache
+  // 模态框对象
+  app.config.globalProperties.$modal = modal
+  // 下载文件
+  app.config.globalProperties.$download = download
+}