Modern attachments (#505)

* Minimum API version is now 100

* Remove old API features

- Anything below API v100 no longer supported

* Reefactor attachment widget to support modern attachment API

* Filter and display attachments correctly

* Refactor

lib/widget/stock/location_display.dart

@@ -140,15 +140,13 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
       }
 
       // Assign or un-assign barcodes
-      if (api.supportModernBarcodes) {
-        actions.add(
-            customBarcodeAction(
-                context, this,
-                location!.customBarcode, "stocklocation",
-                location!.pk
-            )
-        );
-      }
+      actions.add(
+          customBarcodeAction(
+              context, this,
+              location!.customBarcode, "stocklocation",
+              location!.pk
+          )
+      );
     }
 
     return actions;