Switch off autoplay for videos in docs

[Yuri Chornoivan]

Hi,

Some time ago I have added videos to the KStars docs.

https://docs.kde.org/trunk5/en/extragear-edu/kstars/tool-ekos.html

YouTube's videos work fine, but unfortunately the videos from the StellarMate 
site's autoplay ruins the game. :'(

I've tried to add

autoplay: 0;
autostart: 0;

into the div.mediaobject section of kde-default.css (around line 304),
I've tried to add

autoplay="0" autostart="0"

directly into the "embed" tag of HTML code but none of these methods work.

For sure, the videos can be moved to YouTube but... Is there a more elegant 
solution?

Can someone give a hint on how this problem can be solved?

Thanks in advance for your answers.

Best regards,
Yuri