Barcode scanner updates (#562)

* Add BUILDING.md

* Replace scaning library

- Out with qr_code_scanner
- In with flutter_zxing

* Update specs for jdk / kotlin / gradle

- NFI what this all means?

* Refactor barcode scanning widget

* Refactor barcode overlay

* Add handlers

* Update release notes

* Fix AppBar color

* Enhance attachment widget

* remove unused import

* Improved icon

* Select theme from main drawer

lib/widget/refreshable_state.dart

@@ -101,7 +101,7 @@ mixin BaseWidgetProperties {
         },
       ),
       IconButton(
-        icon: Icon(Icons.barcode_reader, color: COLOR_ACTION),
+        icon: Icon(TablerIcons.barcode, color: COLOR_ACTION),
         iconSize: iconSize,
         onPressed: () {
           if (InvenTreeAPI().checkConnection()) {