Put import and export behind auth

vrobbler/templates/scrobbles/scrobble_list.html

@@ -7,10 +7,12 @@
     <div class="d-flex justify-content-between flex-wrap flex-md-nowrap align-items-center pt-3 pb-2 mb-3 border-bottom">
         <h1 class="h2">Dashboard</h1>
         <div class="btn-toolbar mb-2 mb-md-0">
+            {% if user.is_authenticated %}
             <div class="btn-group me-2">
                 <button type="button" class="btn btn-sm btn-outline-secondary" data-bs-toggle="modal" data-bs-target="#importModal">Import</button>
                 <button type="button" class="btn btn-sm btn-outline-secondary" data-bs-toggle="modal" data-bs-target="#exportModal">Export</button>
             </div>
+            {% endif %}
             <div class="dropdown">
                 <button type="button" class="btn btn-sm btn-outline-secondary dropdown-toggle" id="graphDateButton" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                     <span data-feather="calendar"></span>