Zhitao Pan

Add CameraView

11

### Description of Change ### As described in https://github.com/CommunityToolkit/Maui/issues/259#issuecomment-1984316965, this PR adds the initial implementation of the CameraView proposal on MacCatalyst, Windows, Android and iOS, and a corresponding demo page...

Fix CameraView crash when switching camera on Windows and other CameraView enhancements

3

### Description of Change ### - Fixes #2559: In `CameraProvider.windows.cs`, only one instance of `MediaCapture` is instantiated when iterating through the `videoCaptureSourceGroup`. This causes only the first `mediaCapture.InitializeCameraForCameraView()` to be...