[camera_windows] Support camera on windows desktop platform (#4641)
This PR adds a Windows Desktop implementation of [camera plugin](https://pub.dev/packages/camera) using Media Foundation and CaptureEngine interface.
The implementation supports multiple cameras, video preview, and capturing photos and videos. Works with camera plugin and [camera example](https://pub.dev/packages/camera/example).
The current implementation uses FlutterDesktopPixelBuffer, but could be switched to use shared textures or Platform views after those are supported.
Unit tests are partially done; for the CaptureControllerImpl class all falilure code paths are not yet covered.
Still missing some features, like exposure and focus controls. These can be done later with interfaces IAMCameraControl and IAMVideoProcAmp,
Resolves flutter/flutter#41709: [camera] Add Windows support