reorganize layout for expired shared page and not found shared page

src/server/views/layout-growi/expired_shared_page.html

@@ -13,7 +13,8 @@
       data-share-link-created-at="{{ sharelink.createdAt|datetz('Y/m/d H:i:s')}}"
     >
       <div id="share-link-alert"></div>
-      <h2 class="text-muted">
+
+      <h2 class="text-muted mt-4">
         <i class="icon-ban" aria-hidden="true"></i>
         Page is expired
       </h2>

src/server/views/layout-growi/not_found_shared_page.html

@@ -1,13 +1,16 @@
 {% extends './shared_page.html' %}
 
-{% block content_header %}
+{% block html_title %}
+  {{ customizeService.generateCustomTitle('Page is not found') }}
 {% endblock %}
 
-{% block content_page %}
-  <div class="col-md-12">
-    <h2 class="text-muted">
-      <i class="icon-info" aria-hidden="true"></i>
+{% block content_main %}
+  <div class="container-lg">
+
+    <h2 class="text-muted mt-4">
+      <i class="icon-ban" aria-hidden="true"></i>
       Page is not found
     </h2>
+
   </div>
 {% endblock %}