Show reset date below quota progress bars in admin UI

frontend/src/styles.css

@@ -246,6 +246,13 @@ tr:hover {
   font-size: 14px;
 }
 
+.quota-since {
+  display: block;
+  font-size: 10px;
+  color: #aaa;
+  margin-top: 2px;
+}
+
 .progress-bar {
   height: 4px;
   background: #e2e8f0;