Use case or problem
Currently YouTube embeds like  are rendered by default when there in on my view.
It’s good if you only have a few, but if you have MANY YouTube embeds in the same note all renders at the same time, causing seriously performance issues (and I didn’t even click on the video yet!)
Proposed solution
Instead of load the YouTube embed, first display a placeholder with the thumbnail of the video, then when I click on the thumbnail the real YouTube embed is loaded.
This would improve the performance a lot (especially on canvas files).
