[FEATURE] Conditions support in backend layouts

Resolves: #47588
Releases: 6.2
Change-Id: I266f28472ffd78443b107d7ad6577603aecbc584
Reviewed-on: https://review.typo3.org/23697
Reviewed-by: Jo Hasenau
Reviewed-by: Mattias Nilsson
Tested-by: Mattias Nilsson
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe