Update example/README.md's code example

132 embedding v2

Updated Kotlin, Gradle & SDK versions.

Add cutout bottom offset

Properly implement ActivityLifecycleCallbacks public functions

Fixing bug I encountered (Unit defined in android.app.Application.ActivityLifecycleCallbacks)

e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (41, 77): Object is not abstract and does not implement abstract member public abstract fun onActivityPaused(@nonnull p0: Activity): Unit defined in android.app.Application.ActivityLifecycleCallbacks
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (42, 13): 'onActivityPaused' overrides nothing
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (48, 13): 'onActivityResumed' overrides nothing
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (54, 13): 'onActivityStarted' overrides nothing
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (57, 13): 'onActivityDestroyed' overrides nothing
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (60, 13): 'onActivitySaveInstanceState' overrides nothing
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (63, 13): 'onActivityStopped' overrides nothing
e: C:\src\flutter.pub-cache\hosted\pub.dartlang.org\qr_code_scanner-0.0.14\android\src\main\kotlin\net\touchcapture\qr\flutterqr\QRView.kt: (66, 13): 'onActivityCreated' overrides nothing

replace var to let

The example is copied verbatim from ./example/lib/main.dart

For Android people it's not obvious why app crashes.

c.f. https://dart.dev/guides/libraries/private-files

Add optional parameter to use a camera overlay.

- Added optional parameter overlay to QrCodeScanner.
  - If overlay != null, a shapeBorder gets added on top of the scanner view.
  - Added class QrScannerOverlayShape, which is a customizable overlay.
  - updated example to use an overlay.

Simplfiy controller, expose scanDataStream

- MethodChannel is now handled inside the controller
- Removed controller init, pass globalKey as required parameter
- Controller now returns a stream of data
- Updated README.md + example