[BUGFIX] Add missing docs for youtube no-cookie domain change

The doc file was only added for v7, it must also be added to master
and v8.

Resolves: #85029
Related: #84843
Releases: master, 8.7
Change-Id: I2e372eae6bc90a0da0e441237b087b98319a183e
Reviewed-on: https://review.typo3.org/56986


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Tested-by: Mathias Brodala <mbrodala@pagemachine.de>