Fix missing videos / thumbnails

[mbertrand]

Pre-Flight checklist

• [x] Testing
  • [x] Code is tested
  • [x] Changes have been manually tested

What are the relevant tickets?

Fix for #459 , #478

What's this PR do?

• Adds "Video-YouTube-MP4" to the VIDEO_EMBEDDED_MEDIA_IDS list.
• Populates missing video thumbnail locations for Youtube videos

How should this be manually tested?

• Create a courses.json file containing the courses listed in the issue:

  "courses": [
    "res-tll-004-stem-concept-videos-fall-2013",
    "res-18-005-highlights-of-calculus-spring-2010",
    "16-01-unified-engineering-i-ii-iii-iv-fall-2005-spring-2006",
    "2-627-fundamentals-of-photovoltaics-fall-2013",
    "7-01sc-fundamentals-of-biology-fall-2011",
    "6-00-introduction-to-computer-science-and-programming-fall-2008"
  ]
  }

• Run node . -i input -o output -c courses.json --download
• Git clone ocw-hugo-themes and set .env values, including:

  COURSE_CONTENT_PATH=/path/to/ocw-to-hugo/output
  OCW_TEST_COURSE=<one-of-the-courses-above>

• Run npm run start:course
• Check that the missing video for the course is no longer missing.
• For the last course 6-00-introduction-to-computer-science-and-programming-fall-2008, make sure there is a thumbnail for the 1st video on the video gallery page.

After ocw-to-hugo is run again with these changes, they will need to be migrated to ocw-studio somehow without running the import-ocw-course-sites command. The fix for #459 will add a new markdown file for each previously missing video, these need to be added to studio and github. The fix for #478 changes markdown for existing video markdown files.

[pdpinch]

After this is reviewed and merged, what is the plan for updating courses with missing videos? How/can we do it without overwriting changes that have been made in ocw-studio?

[mbertrand]

Not sure if we can do it without overwriting changes via another import - @gumaerc?

[mbertrand]

Is anyone actually updating these old courses? Maybe we could do a targeted import of only courses that have Video-YouTube-MP4 video resources.