* Add NSFW flags to videos so the publisher can add more NSFW context
* Add NSFW summary to videos, similar to content warning system so the
publisher has a free text to describe NSFW aspect of its video
* Add additional "warn" NSFW policy: the video thumbnail is not blurred
and we display a tag below the video miniature, the video player
includes the NSFW warning (with context if available) and it also
prevent autoplay
* "blur" NSFW settings inherits "warn" policy and also blur the video
thumbnail
* Add NSFW flag settings to users so they can have more granular
control about what content they want to hide, warn or display
