Using references instead of absolute URLs has the following
advantages:

- If a target section is moved, the URL in a :ref:
  linking to it is updated automatically
- It is possible to maintain the links to the other docs
  repository in a central place (Settings.cfg). This way,
  it is possible to link to the same version of a manual
  in a lower branch (e.g. 10.4) by changing the link in
  one place

The above results in a better user experience (stay in
information for same version when linking across docs
repos) and less broken links (in the future).

Resolves: #95948
Releases: master, 10.4
Change-Id: I84d801a75424bd94b4fa15aecb17a6085af07c36
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72145


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>