[TASK] Add documentation group Dashboard widgets

A widget group is added to the TYPO3 add widget modal with
all the documentation widgets

Resolves: #90457
Releases: master
Change-Id: I56afc843f1f1b3ab08d97213e68c0c7b862e17f8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63348


Tested-by: Daniel Siepmann <coding@daniel-siepmann.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Daniel Siepmann <coding@daniel-siepmann.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>