[TASK] Refactor t3skin / re-work HTML / move to extension

Specific CSS styles that are only needed is a single place should
be held in that specific place also. Moves CSS styles that are only
used in one place to that specific location. These styles are also
only loaded when needed.

Also refactors HTML output of backend modules to be more
HTML5 standard conform. This allows us to remove a lot of CSS.

CSS/less was touched for:
About, About modules, Wizards, Permissions, Setup, TS Template.

Resolves: #62157
Related: #62041
Releases: master
Change-Id: I12a2c8fd0ad5be294d7440f08d8fe96f28841bfc
Reviewed-on: http://review.typo3.org/33256
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Frank Nägler <typo3@naegler.net>
Tested-by: Frank Nägler <typo3@naegler.net>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>