[TASK] Doctrine: Migrate ext:core Registry

Migrate Registry class to doctrine and clean up the class
along the way. Split off those unit tests that mocked
database stuff and migrate them to functional tests.

Change-Id: I5c29ab8c6ff3fa9c77e5bc886988628d2c3d7fa5
Resolves: #77223
Releases: master
Reviewed-on: https://review.typo3.org/49175


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>