We should have a block whose sole purpose it is to show a standardized OpenGraph box with site icon, title description and link. Kind of like what you see on this page: https://developers.facebook.com/tools/debug/og/object/?q=https%3A%2F%2Fgithub.com%2FWordPress%2Fgutenberg

The block would be inserted as a placeholder, like the Embed block. When an arbitrary link is pasted in, the block crawls out and fetches the OG data and populates it.

It would be good to have this be a separate block to the Embed block, as you might want to opengraph link to a youtube video without embedding it.