[BUGFIX] Fix fatal error in PageLayoutController

Move the module template initialization where it is clear
that the BE user really has access to the page.

Additionally clean up other mistakes in the code.

Change-Id: I9977c966ef1f9b892b53d73c784d27ca1c5fc006
Resolves: #70758
Releases: master
Reviewed-on: http://review.typo3.org/44077


Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Marcus Schwemer <ms@schwemer.de>
Tested-by: Marcus Schwemer <ms@schwemer.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>