Investigate oEmbed/noembed plugins

e.g.

https://github.com/Appleman1234/arisu/tree/master/Link

Depending on the backend, it would be good to have *well designed* /brief previews available for backends which do not have them.
For backends which have gnarly previews, like gitter, an oEmbed/Noembed approach will probably be less annoying, and the bot could also scream at people who drop links into the chat which show huge preview boxes.

Start by reviewing the linked arisu Link example and identifying how Corobo's backends currently handle link previews. Define which backends need /brief previews, how oEmbed or Noembed would address gnarly previews such as Gitter, and what behavior should be considered complete.

Written by the indexing model from the issue text.