[TASK] Base DynTab on Bootstrap and re-color

Base the DynTab tabs on <ul> and Bootstrap nav-tab. Also
base the tab colors on Bootstrap variables and remove colors
as well as gradient.

Related: #62002
Releases: master
Change-Id: Ibff2f3633512538b323af465e55ef9d08fc8bfd3
Reviewed-on: http://review.typo3.org/33130
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>