activate live statistics via settings

src/app/admin/settings/Settings.svelte

@@ -71,6 +71,17 @@
           onChange: dynamicSettings.signupSetDisabledSubtext
         }
       ]
+    },
+    {
+      name: 'Live-Statistiken',
+      entries: [
+        {
+          name: 'Aktiviert',
+          type: 'checkbox',
+          value: dynamicSettings.liveStatisticsEnabled(),
+          onChange: dynamicSettings.liveStatisticsSetEnabled
+        }
+      ]
     }
   ];