[TASK] Drop single column view in PageLayoutView

The single column view was unused in the core for ages.
Remove this leftover code now.

Resolves: #68021
Releases: master
Change-Id: I133338953175e3eb151f05b20f5a8f1eeb253444
Reviewed-on: http://review.typo3.org/41062


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Stephan Großberndt <stephan@grossberndt.de>