[BUGFIX] Inconsistent naming confirmation/confirm

Various settings and templates use "confirmation" in names.
However, "confirm" is actually used in the controller.

Change-Id: Ic70e80c8f524323bcd81b478c43363323db13a3d
Reviewed-on: https://review.typo3.org/31546
Reviewed-by: Sebastian Fischer <typo3@evoweb.de>
Tested-by: Sebastian Fischer <typo3@evoweb.de>