[TASK] Change fetch of maximum version using LEFT JOIN

Currently, the method fetchMaximalVersionsForAllExtensions uses a
subselect to determine the highest available version. This solution is
rather inefficient and incomptabile to DBAL. The query is replaced by
a LEFT JOIN.

Resolves: #60857
Releases: 6.2, 6.3
Change-Id: I7ae3c523259bf260c41080aee269f6df33edb408
Reviewed-on: http://review.typo3.org/32288
Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>