Add edX video ID section

Added the video_course.rst file to describe what course teams do after automated processing is complete.
@nasthagiri, @frrrances, @WatsonEmily , @lou-wang, @srpearce 
@mhoeber, @catong FYI.
This line was confusing to me. I read it as "The Editing: /  Video popup opens to the Basic tab." Perhaps say "A popup titled "Editing: Video" opens to the Basic tab"