Is your feature request related to a problem? Please describe.
Outside of event pages, bytesize links need to be embedded with "complex" html. It would be friendlier to contributors
to only need to use a markdown link.

Describe the solution you'd like
Replace the need for:

<div class="ratio ratio-16x9">
    <iframe width="560" height="315" src="https://www.youtube.com/embed/xuNYATGFuw4" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</div>

with

[Bytesize talk: Title here](https://www.youtube.com/embed/xuNYATGFuw4)

Add a custom function to translate the markdown link into the required html.

Additional context
#1063 (comment)