[BUGFIX] Provide full url as origin for embedded Youtube videos

To use the javascript API for embedded Youtube videos the documentation
recommends to provide the "full website url" as origin parameter

Change-Id: I318083b4c67b48c7eb708e54b11cd8dd1c69d646
Resolves: #77409
Releases: master, 7.6
Reviewed-on: https://review.typo3.org/49416


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Tested-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>