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/inventree/model.dart

@@ -148,6 +148,23 @@ class InvenTreeModel {
   // Legacy API provided external link as "URL", while newer API uses "link"
   String get link => (jsondata["link"] ?? jsondata["URL"] ?? "") as String;
 
+  /* Extract any custom barcode data available for the model.
+   * Note that old API used 'uid' (only for StockItem),
+   * but this was updated to use 'barcode_hash'
+   */
+  String get customBarcode {
+    if (jsondata.containsKey("uid")) {
+      return jsondata["uid"] as String;
+    } else if (jsondata.containsKey("barcode_hash")) {
+      return jsondata["barcode_hash"] as String;
+    } else if (jsondata.containsKey("barcode")) {
+      return jsondata["barcode"] as String;
+    }
+
+    // Empty string if no match
+    return "";
+  }
+
   Future <void> goToInvenTreePage() async {
 
     if (await canLaunch(webUrl)) {

lib/inventree/stock.dart

@@ -276,8 +276,6 @@ class InvenTreeStockItem extends InvenTreeModel {
     });
   }
 
-  String get uid => (jsondata["uid"] ?? "") as String;
-
   int get status => (jsondata["status"] ?? -1) as int;
 
   String get packaging => (jsondata["packaging"] ?? "") as String;