[BUGFIX] Include accidentally removed autoload entries

Some of the removed entries have no pendant in the
class alias map, which causes a fatal error e.g. in
RTE image selector.

Add them again and fix the class definition of
ImageFolderTree.

Fixes: #42677
Releases: 6.0

Change-Id: Ib6d6f2045012bac08feb612489a6334d3cb95649
Reviewed-on: http://review.typo3.org/16193
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel