Create nuxtPicture element that can handle multiple aspectratios

[tfjordside]

Problem
Currently we have a problem where multiple nuxt pictures are needed, if you want a portrait image on mobile and a landscape image on desktop. It is nicely described here: nuxt/image#309

Cowboy solution:
Creating a NuxtSource element that spits out source that then gets wrapped in a picture element.
https://github.com/limbo-works/danish-crown-external-websites/commit/913d6cce1f0d18d5680f02529d639e8d8b7ce08e#diff-66a9c6da5f0908f8b0a7eb47ad02682783673e66689d3bf8ce97b129c89fd134R103

Wanted solution:
A solution where we can add a prop to NuxtPictureExt
and the sources are then created from using useImage() from nuxt/image and then wrapped in a default picture tag instead of NuxtPicture
Fallback without the string is just sending the solution to NuxtPicture as now.

Questions:
Should we allow for art direction (changing images to another source based on screensize)

Suggested syntax:

:versions="

{ 
    '600': { aspectRatio: 1/1, size: '100w', src: ''},
    '>=1024': { aspectRatio: 16/9, size: '60w', src: ''},
    '>=1920': { aspectRatio: 21/9, size: '80w', src: ''},
}

"