[BUGFIX] Add class "template" to ext_autoload.php

Somehow sometimes class template is not autoloaded
by the TYPO3 core, so it has to be added to file
ext_autoload.php

Resolves: #57741
Releases: 1.9.1
Change-Id: I3f2656f205257bd2805d697fc9a64ede826917f2
Reviewed-on: https://review.typo3.org/30375
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Alexander Schnitzler
Tested-by: Alexander Schnitzler