[RELEASE] Release of TYPO3 6.0.3

Change-Id: I962e723070598c7cf235bd7ff91432a38bb179ce
Reviewed-on: https://review.typo3.org/18747
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team
[TASK] Set TYPO3 version to 6.0.4-dev

Change-Id: Ied84dbe8f0b087b325705329414b7db0dc73b773
Reviewed-on: https://review.typo3.org/18748
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team