[feature] video-embedding: youtube-alternative "invidious"; federated video hosting "PeerTube"; HTML5 video support -- support for other video providers than the "big players".

If there is youtube-embedding implemented via `{%youtube %}` syntax, I suggest that there is also added support for privacy-friendly youtube mirrors like iteroni.com.

And I also suggest embedding possibility of "[fediverse](https://en.wikipedia.org/wiki/Fediverse)"-[PeerTube](https://en.wikipedia.org/wiki/PeerTube), a federated video hosting software.

Thus not to provide only embedding for the big commercial ones.

Other suggestion (which should work with any place where the video file's URL is directly accessible) would be if a file format that the browser can play directly can be embedded in a way that generates the necessary HTML5-structures so that direct in-browser play is offered. This would be a general solution for many circumstances (not youtube).