frontend: show logout button only if user/pass is set

src/frontend/js/app.ts

@@ -90,6 +90,7 @@ export default {
       },
       'refreshRate': s.refresh_rate,
       'authenticated': app.authenticated,
+      'requiresAuth': app.requiresAuth,
       'feed_errors': {},
 
       'refreshRateOptions': [

src/frontend/js/templates/index.html

@@ -117,8 +117,8 @@
                         </button>
                     </div>
                 </div>
-                <div class="dropdown-divider" v-if="authenticated"></div>
-                <button class="dropdown-item" v-if="authenticated" @click="logout()">
+                <div class="dropdown-divider" v-if="requiresAuth"></div>
+                <button class="dropdown-item" v-if="requiresAuth" @click="logout()">
                     <v-icon class="mr-1" name="log-out" />
                     {{ $t('log_out') }}
                 </button>