Scanner wedge mode (#437)

* Add code_scan_listener package

* Implement wedge controller widget

* Update barcode settings widget

- Allow user to choose which barcode scanner to use

* Fix typo

* Select barcode scanner widget based on user preference

* Fix rendering issues for wedge controller

* Update release notes

* Add unit test for wedge scanner widget

- Required some tweaks to other code

* Use better library

- https://github.com/fuadreza/flutter_barcode_listener
- Fork of https://github.com/shaxxx/flutter_barcode_listener
- Properly handles key "case" issues (shift, essentially)
- Verified that it works correctly for multiple character types

* Local copy of code, rather than relying on package which is not available on pub.dev

* Fix unit test

lib/l10n/app_en.arb

@@ -118,6 +118,12 @@
   "barcodeScanAssign": "Scan to assign barcode",
   "@barcodeScanAssign": {},
 
+  "barcodeScanController": "Scanner Input",
+  "@barcodeScanController": {},
+
+  "barcodeScanControllerDetail": "Select barcode scanner input source",
+  "@barcodeScanControllerDetail": {},
+
   "barcodeScanDelay": "Barcode Scan Delay",
   "@barcodeScanDelay": {},
 
@@ -169,6 +175,12 @@
   "building": "Building",
   "@building": {},
 
+  "cameraInternal": "Internal Camera",
+  "@cameraInternal": {},
+
+  "cameraInternalDetail": "Use internal camera to read barcodes",
+  "@cameraInternalDetail": {},
+
   "cancel": "Cancel",
   "@cancel": {
     "description": "Cancel"
@@ -1003,6 +1015,12 @@
   "scanIntoLocationDetail": "Scan this item into location",
   "@scanIntoLocationDetail": {},
 
+  "scannerExternal": "External Scanner",
+  "@scannerExternal": {},
+
+  "scannerExternalDetail": "Use external scanner to read barcodes (wedge mode)",
+  "@scannerExternalDetail": {},
+
   "scanReceivedParts": "Scan Received Parts",
   "@scanReceivedParts": {},