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/l10n/app_en.arb

@@ -274,6 +274,12 @@
   "damaged": "Damaged",
   "@damaged": {},
 
+  "colorScheme": "Color Scheme",
+  "@colorScheme": {},
+
+  "colorSchemeDetail": "Select color scheme",
+  "@colorSchemeDetail": {},
+
   "darkMode": "Dark Mode",
   "@darkMode": {},