[TASK] Adjust Logos to new style-guide

TYPO3 is changing and so is the logo.
Secondary color green is dropped and replaced by orange.
Also the signet moves to the left.

Adjusts logos/images/icons/files in backend to new brand definition.

Fixes: #41704
Releases: 4.6, 4.7, 6.0
Change-Id: I34c80b085ef6b6efaffe2de4b67bb47c79b570ec
Reviewed-on: http://review.typo3.org/15392
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer
Reviewed-by: Mattias Nilsson
Tested-by: Mattias Nilsson
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert