[Feature] Informationbox

Enables blocks with own classes for wiki entries.

!!! className
MyText
!!!

Will be rendered as

<div class="className">MyText</div>

This solves also #42275 because:

!!! floatRight
{TOC}
!!!

is possible.

Delivered Classes right now: floatRight, floatLeft, clear

Change-Id: Iffd5e2a6fe330ed80506ebfd9d0b08648d829f94
Resolves: #42480 @1h
Resolves: #42275
Reviewed-on: https://review.typo3.org/26449
Reviewed-by: Bastian Bringenberg
Tested-by: Bastian Bringenberg