The documentation module brings back access to extension manuals and
lets official TYPO3 documents (such as guidelines, tutorials and
references) as well as custom documents to be listed in a central place.

Resolves: #50486
Releases: 6.2
Change-Id: Ib35a48f72682844f1bfe569763a561a89e7d810b
Reviewed-on: https://review.typo3.org/22622
Reviewed-by: Francois Suter
Tested-by: Francois Suter
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Stefan Neufeind
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers