[TASK] Remove fixed width for Content Element Wizard tabs content container

When using Content Element Wizard configured to render items with
tabs their body container has fixed width of 680px. This leads
to visual problems when using some extra tabs registered - their
titles are rendered outside body content. This patch removes
fixed width and some other styles that are not needed. For example
there are some styles for tables inside tab content but items are
rendered in lists not tables so we can remove them.

Change-Id: I1d749649ffa86cd2220460f1ebf4894aca98f4bc
Resolves: #53904
Releases: 6.2
Reviewed-on: https://review.typo3.org/26906
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Marcin S?gol
Tested-by: Marcin S?gol
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny