[TASK] Remove references to template.php in EXT: versions

Former template.php file is cued for removal. Versions backend
module still includes the empty casing "template.php".

Change-Id: I3b9e86346d9a179c272a39adccf89b9eced7179a
Resolves: #48124
Releases: 6.2
Reviewed-on: https://review.typo3.org/20726
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind