Connect giftcards with customer accounts (#5126)

Connect giftcards with customer accounts, show giftcards during checkout and in account , show giftcard list in backend customer view

src/pretix/static/pretixpresale/js/ui/main.js

@@ -222,6 +222,12 @@ var form_handlers = function (el) {
             }
         });
     }
+
+    el.find('.use_giftcard').on("click", function () {
+        var value = $(this).data('value');
+        $('#id_payment_giftcard-code').val(value)
+    })
+
 };
 
 function setup_basics(el) {