A TypoScript Reference documentation widget is added.

Resolves: #90435
Releases: master
Change-Id: I31ea8a2be4bc55d6cdcecac5c9abbe95016b739e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63323


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Siepmann <coding@daniel-siepmann.de>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Riny van Tiggelen <info@online-gamer.nl>
Reviewed-by: Daniel Siepmann <coding@daniel-siepmann.de>
Reviewed-by: Richard Haeser <richard@maxserv.com>