Fixes for "duplicate stock item" form

- Redirect to the new stock item
- Display a success message

InvenTree/stock/templates/stock/item_base.html

@@ -462,9 +462,7 @@ $("#print-label").click(function() {
 {% if roles.stock.change %}
 $("#stock-duplicate").click(function() {
     // Duplicate a stock item 
-    duplicateStockItem({{ item.pk }}, {
-        follow: true,
-    });
+    duplicateStockItem({{ item.pk }}, {});
 });
 
 $('#stock-edit').click(function() {

InvenTree/templates/js/translated/stock.js

@@ -294,7 +294,17 @@ function stockItemGroups(options={}) {
  */
 function duplicateStockItem(pk, options) {
 
-    // First, we need the StockItem informatino
+    // If no "success" function provided, add a default
+    if (!options.onSuccess) {
+        options.onSuccess = function(response) {
+
+            showAlertOrCache('{% trans "Stock item duplicated" %}', true, {style: 'success'});
+
+            window.location.href = `/stock/item/${response.pk}/`;
+        }
+    }
+
+    // First, we need the StockItem information
     inventreeGet(`/api/stock/${pk}/`, {}, {
         success: function(data) {