[TASK] About modules: add two-column layout

Remove max width of the content. Add a fluid two-column
layout and add more vertical space between the submodules.
Get rid of the unneeded css file.

Resolves: #63476
Releases: master
Change-Id: Ibdbe64959ee5815e32116d54f822303c32eecf76
Reviewed-on: http://review.typo3.org/41716


Reviewed-by: Frederic Gaus <frederic.gaus@flagbit.de>
Tested-by: Frederic Gaus <frederic.gaus@flagbit.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>