Have a "Show more related articles" button

[LeMurphant]

@Algon-33 would like to have the option to show more than 3 related articles. @melissasamworth wanted to keep the 3 by default since we don't want to overwhelm with options.

Right now, my understanding is that we truncate after 3 (only keeping live questions), ordered in some trivial way.

Algon suggests that we could list up to 3 by default, and if there are more than 3, we could have a button that allows a user to see them all. Melissa, would you be OK with that? If so, what would you like the button to look like?