Add art direction

[alexgoff]

Is your feature request related to a problem or planned work?
Images are often formatted in portrait or landscape orientations and do not scale well to other sizes, either leaving too much white space or inappropriately scaling down the image.

Describe the solution you'd like and scope of work
Add a second asset field to the Image content block that specifies a portrait layout image and implement a condition in the client to parse into a picture element instead of a single img element.