[models] - add 'external video' for traces form

If the trace is a video, can we see the video immediately on the trace page the website?

(Comment: When there is a link to vimeo, it indicates it cannot play it when the video is embedded in another site.) Being able to click on an active link in the text would already be better, and a screenshot of the film.

vimeo and sound url. Links are not active: examples:

https://eavatea.jubilee-art.org/practice/2 https://index.nadine.be/live-conversation-commons-to-coop/ https://www.youtube.com/watch?v=ZfaFriFAz1k