[TASK] Move t3lib/stddb/DefaultConfiguration.php to EXT:core

Moves t3lib/stddb/DefaultConfiguration.php to
EXT:core/Configuration/DefaultConfiguration.php

Change-Id: I8a4e00247e1ab27c566f8868744aa87ca615ad38
Resolves: #45188
Releases: 6.1
Reviewed-on: https://review.typo3.org/18042
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn