[Frontend] Add chat and SlidesLive to abstract modal

[titipata]

Our Neuromatch talk shows information such as title, author, abstract, ...

However, we might have to add functionality to add

• SlidesLive
• Rocket Chat

Please see http://www.mini-conf.org/poster_BygXFkSYDH.html for the size of embedded SlidesLive. We might have to adjust details a bit if there is a SlidesLive embed.