Add autoplay YT option

...ations/0310_alter_districtarticlepage_content_and_more.py

...ons/migrations/0067_alter_electionsarticlepage_content.py

...migrations/0150_alter_mainarticlepage_content_and_more.py

shared/blocks/parents/video.py

...yleguide2/includes/atoms/youtube_video/youtube_video.html

...grations/0123_alter_uniwebarticlepage_content_and_more.py

uniweb/models.py