Use media browser in Panopoly 2.x for all fields that used it in Panopoly 1.x

In Panopoly 1.x, we strived to use the media browser on as many file and image fields as was possible and made sense.

In Panopoly 2.x, we aren't using the media browser on all the same fields, for example, on the image field on Image widgets.

This issue is to go through Panopoly 2.x, evaluate all the image/file fields, and use the media browser on all of those where it was used on Panopoly 1.x and it still makes sense.