FormBuilderImagePicker preview and camera callback

[JaviCore]

So besides the problems with initial value (#607 #622) I have also noticed than when you set the preview size the camera icon is not centered as well as the delete one. This basically causes you to have to expand your widget in order to be able to change the image and such.

Also camera callback doesn't trigger half of the time until I manually go back and select the camera again to take a second picture.
This is all in emulator though, didn't have the time to try a real device.

Lastly I was wondering if adding editing functions when selecting an image is something that might be implemented in the future.

Thanks

Edit: using the lastest package and flutter stable 1.22.5

[deandreamatias]

Closed because this widget is moved to https://github.com/danvick/form_builder_image_picker