Changing image size in MWMediaEditDialog

Adding the ability to edit image size in the media edit dialog.
The size is now a separate widget.

The following changes were made:
* The dialog was changed to a booklet with 'general settings' and
  'advanced settings', in preparation for other edit features.
* The original image maximum size is fetched from the API and cached.
* Maximum size is limited to the image's original maximum size.
* Aspect ratio is kept when changing height or width, using original
  image size to preserve a sane ratio through the MediaSizeWidget.
* If an error is found in the size, the image will retain its previously
  set dimensions.

Depends on MediaSizeWidget: I3d0f9348a52

Bug: 38129
Change-Id: I2946fb21c46ce05583b219f665ef68928188899e