localStorage操作统一使用localStorageUtils完成

bookshelfplus-frontend/views/component/header.html

@@ -9,6 +9,7 @@
 <script src="/assets/lib/axios/0.26.1/axios.min.js"></script>
 
 <script src="/assets/javascripts/httpRequest.js"></script>
+<script src="/assets/javascripts/localStorageUtils.js"></script>
 <script>
     // API地址
     const APIHOST = '<%= global.site.api.prefix %>';

bookshelfplus-frontend/views/component/navbar.html

@@ -16,8 +16,9 @@
     </div>
 </div>
 <script>
-    if (localStorage.getItem("token"))
+    if (localStorageUtils.getLoginStatus()) {
         $("#dashboard").html("后台");
+    }
 
     function navbarHighlight() {
         // 导航栏中突出当前页面