Make playing video become PiP/mini-player on scroll-away?

[mxmilkiib]

This would be great, I don't think a video should stop playing if I want to continue scanning my feed at the same time

Relates to #7451, but that's a different question.

[Git-NPC]

I'd love this! Sometimes I want to scroll the comments while watching a video.

Also make the video continue where it left off when leaving the page/scrolling and not starting over.