Endpoint for fetching latest video from playlists

It would be useful to get the latest video of a set of playlists.

For example: If I provide three playlist IDs, it should return a single video which is also the most recent of the three playlists.

This feature would allow us to implement the "What's New" video from https://ecdtools.eclipse.org/ using the media-link api. Currently, ECDTools uses the YouTube Data API directly.