News : Show article summary in Headlines template

[plamarque]

Is your feature request related to a problem? Please describe.
Currently, the Show article summary option can't be enabled when we choose the Headlines News list template.

Describe the solution you'd like
allow to switch it on and display summaries on the side news below the title

see where on this example

no need to display on main card IMO.

Also consider enabling summary display option on other templates such as : cards, stories and mosaic

[srenault-meeds]

cc @Julien-Dubois-eXo