站点选择下拉框的数据获取、存储处理逻辑更新，解决因为多层router-view嵌套，二级路由以上页面不会被缓存的而导致单站监控页面站点选择下拉框闪烁的问题

src/store/index.js

@@ -6,6 +6,7 @@ import user from './modules/user'
 import tagsView from './modules/tagsView'
 import permission from './modules/permission'
 import settings from './modules/settings'
+import ems from './modules/ems'
 import getters from './getters'
 
 Vue.use(Vuex)
@@ -17,7 +18,8 @@ const store = new Vuex.Store({
     user,
     tagsView,
     permission,
-    settings
+    settings,
+    ems
   },
   getters
 })