[FEATURE] Backend skin: Fresh table style

Ease the table layout and embrace striped zebra style.
Remove borders - soften the header.

Resolves: #62159
Releases: master
Change-Id: I8b2e47158a5f9be61f184b928363ba9c5f4110c0
Reviewed-on: http://review.typo3.org/33258
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>