[camera] add video stabilization

[ruicraveiro]

Adds support for video stabilization to camera_platform_interface, camera_avfoundation, camera_android_camerax and camera packages.

The video stabilization modes are defined in the new VideoStabilizationMode enum defined in camera_platform_interface:

/// The possible video stabilization modes that can be capturing video.
enum VideoStabilizationMode {
  /// Video stabilization is disabled.
  off,

  /// Basic video stabilization is enabled.
  /// Maps to CONTROL_VIDEO_STABILIZATION_MODE_ON on Android
  /// and throws CameraException on iOS.
  on,

  /// Standard video stabilization is enabled.
  /// Maps to CONTROL_VIDEO_STABILIZATION_MODE_PREVIEW_STABILIZATION on Android
  /// (camera_android_camerax) and to AVCaptureVideoStabilizationModeStandard
  /// on iOS.
  standard,

  /// Cinematic video stabilization is enabled.
  /// Maps to CONTROL_VIDEO_STABILIZATION_MODE_PREVIEW_STABILIZATION on Android
  /// (camera_android_camerax) and to AVCaptureVideoStabilizationModeCinematic
  /// on iOS.
  cinematic,

  /// Extended cinematic video stabilization is enabled.
  /// Maps to AVCaptureVideoStabilizationModeCinematicExtended on iOS and
  /// throws CameraException on Android.
  cinematicExtended,
}

There is some subjectivity on the way with which I mapped the modes to both platforms, and here's a document that compares the several modes: https://docs.google.com/spreadsheets/d/1TLOLZHR5AcyPlr-y75aN-DbR0ssZLJjpV_OAJkRC1FI/edit?usp=sharing, which you can comment on.

List which issues are fixed by this PR. You must list at least one issue. Partially implements https://github.com/flutter/flutter/issues/89525

Pre-launch Checklist

• [x] I read the Contributor Guide and followed the process outlined there for submitting PRs.
• [x] I read the Tree Hygiene page, which explains my responsibilities.
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• [x] I signed the CLA.
• [x] The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• [x] I linked to at least one issue that this PR fixes in the description above.
• [x] I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• [x] I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style, or this PR is exempt from CHANGELOG changes.
• [x] I updated/added relevant documentation (doc comments with ///).
• [x] I added new tests to check the change I am making, or this PR is test-exempt.
• [x] All existing and new tests are passing.

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