Add support for image-props

Images are defined like this:

 title: Image
	type: object
	examples:
	  - src: "https://images.unsplash.com/photo-1484959014842-cd1d967a39cf?ixlib=rb-1.2.1&ixid=Mnw
xMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1770&q=80"
		alt: "Woman playing the violin"
		width: 1770
		height: 1180
	$ref: "json-schema-definitions://canvas.module/image"

atm Drupal canvas does not support picking aspect-ratios or image-styles - Related: #3562276: SDC: support selection of image styles or aspect ratio

However, selecting images is supported via the noted json-schema-type.

We need to extend nuxt-component-preview to allow adding this metadata easily, together with a suiting example.

Then later on, we can look into focal-point support by passing-through the focal-point, so the frontend can apply it, and/or providing a desired aspect-ratio, minimum and/or minimum dimensions in the image metadata.

implemented and added a PR here: https://github.com/drunomics/nuxt-component-preview/pull/64

That works, but fails with canvas due to errors during url-rewriting. we need to add this as well.

tested successfully :-) use nuxt-component-preview beta3 or later to use it! See README for usage details.