[!!!][TASK] Drastically speed up `bin/typo3 cleanup:flexforms`

CLI command `bin/typo3 cleanup:flexforms` of ext:lowlevel
is extremely slow due to its page-tree-based strategy.
It can run many hours on seasoned instances.

Rewriting the command towards a TCA table
based approach speeds it up dramatically.

Example data point with my tiny test DB: Before ~450
seconds, with patch ~0.5 seconds.

Resolves: #102181
Releases: main
Change-Id: I9451b40953c3a6fa02c690591751e1170d486beb
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81436


Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>