Support for Instagram stories

[xyzlabc]

Checklist

• I'm reporting a site feature request
• I've verified that I'm running youtube-dl version 2020.06.06
• I've searched the bugtracker for similar site feature requests including closed ones

Description

Please can we get support for saving Instagram stories? Videos of important events such as protests etc. are often shared this way, and as an ephemeral medium are liable to be lost.

Example links may not work as videos expire after 24-hours, but here is one anyway:

https://www.instagram.com/stories/ladygaga/2326418290539747009/

These links can be found by logging in to Instagram using its web version and clicking on the profile picture of a user with a story to view the story. The link in the browser's URL bar changes with each video in the story.

Invoking youtube-dl for the example URL currently gives this error:

[generic] 2326418290539747009: Requesting header
WARNING: Falling back on generic information extractor.
[generic] 2326418290539747009: Downloading webpage
[generic] 2326418290539747009: Extracting information
ERROR: Unsupported URL: https://www.instagram.com/stories/ladygaga/2326418290539747009/