[TASK] Move classAliasMaps into compatibility6 extension part 4

This is the sysext:dbal class alias part

Change-Id: I3ab4681527f7f2bbaf1a0b9d314c06057927c2cc
Resolves: #62847
Related: #62013
Releases: master
Reviewed-on: http://review.typo3.org/33975
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>