4148 [various] Prepare plugin repo for binding API improvements (cla: yes, waiting for tree to go green, p: camera, p: video_player)

4152 [webview_flutter] Move webview_flutter to webview_flutter/webview_flutter (cla: yes, waiting for tree to go green, p: webview_flutter, platform-ios, platform-android)

4158 [camera] Fix coordinate rotation for setting focus- and exposure points on iOS (cla: yes, waiting for tree to go green, p: camera, platform-ios)

4164 [camera_web] Add CameraOptions used to constrain the camera audio and video (cla: yes, waiting for tree to go green, p: camera, platform-web)

4166 [image_picker_for_web] Support multiple pick. Store name and other local file properties in XFile. (cla: yes, waiting for tree to go green, p: image_picker, platform-web)