Add view mode for 'Card'

[markconroy]

Lots of websites use a "Card" view mode. Our current profile only allows teaser as a view mode, which is fine for some listings like a search result or service listing, but often we might like a slightly different layout, such as a featured news like what is on the Brighton-Hove homepage.

Once we have this as a view mode, I'd suggest we place a template called node--card.html.twig in the localgov_skeleton theme so all themes can use the HTML from it and not invent their own per theme/site.

[msayoung]

I think this is a great idea @markconroy

[markconroy]

@msayoung assigning you and me to this. Let's see how gets to it first.