Introduced alias field to get IDs independently from autoincremented UIDs

Change-Id: I6b9c8f5a78903b2231109fc5faaab993a01e8ff6
Reviewed-on: https://review.typo3.org/24118
Reviewed-by: Jo Hasenau
Tested-by: Jo Hasenau
Reviewed-on: https://review.typo3.org/25129