Add support for crowdcast.io

[DrHyde]

Checklist

• I'm reporting a new site support request
• I've verified that I'm running youtube-dl version 2020.09.20
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that none of provided URLs violate any copyrights
• I've searched the bugtracker for similar site support requests including closed ones

Example URLs

• Single video: https://www.crowdcast.io/e/gresham-mars

Description

Requires registration, which is free.

I assume this will be fairly simple to automate. Clicking on the play button in a browser with Chrome developer tools turned on, I can currently search the list of URLs that gets spat out for 'm3u8', copy the URL to a command like ffmpeg -i https://blahblahblah Gresham-Mars.mp4 and it just Does The Right Thing.