[CLEANUP] Remove browser hacks in CSS files

Several browser hacks in backend CSS files
can now be removed as browser don't need
to use -moz or -webkit. Also, several filter
and IE7 star hacks can be removed.

Resolves: #60526
Releases: 6.3
Change-Id: I45aa45a51abe5ab0a6986f1bf0bfd324a23ccd12
Reviewed-on: http://review.typo3.org/31759
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>