New barcode actions (#218)

* Bump release notes

* Adds method for linking custom barcodes

* Custom getter method for determining if an item has barcode data

* Add method to check if the API supports "modern" barcodes

* Refactor custom barcode implementation for StockItem

- Needs testing

* Unit testing for linking and unlinking barcodes

* Fixes

* Refactor code for "custom barcode action" tile

* Add custom barcode action to StockLocation

* Add extra debug to debug the debugging

* Unit test fix

* Change scope I guess?

* remove handler test

lib/widget/location_display.dart

@@ -453,6 +453,12 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
             )
           );
         }
+
+        if (InvenTreeAPI().supportModernBarcodes) {
+          tiles.add(
+            customBarcodeActionTile(context, location!.customBarcode, "stocklocation", location!.pk)
+          );
+        }
       }
     }