Video thumbnail or icon to open expanding div to display embedded video inline

Background

• We currently have the ability to add a YouTube icon next to a video link, or to embed the video.
  • YT icon/link: not an optimal experience, as the user must open a new browser tab
  • Full-size embed: takes up a lot of space on the page and can make it harder to browse.

Proposal

• It would be optimal to have a middle-ground option where we display a video thumbnail or icon (plus title and maybe summary) which opens an 'expanding div' to display the embedded video inline.
  • An example solution is displayed on this page.
• Decide whether to keep or update the other formats.
• Updates to the Documentation Style Guide video section; not just how to include the new format, but how/when to choose it vs the others.