[TASK] Performance improvement on indexing process

Use exec_INSERTmultipleRows instead of exec_INSERTquery for
submitting indexer results to table index_rel. This may save _a lot_
of I/O load, especially when a page contains many words to be indexed.

Skip words marked as stopWords to prevent flooding of index_rel table.

Resolves: #38742
Resolves: #18599
Releases: master
Change-Id: Ia729e6632124692cabe7d5ebe079db7d6795b809
Reviewed-on: http://review.typo3.org/20275
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
[TASK] CSS: Remove horizontal gray lines "uppercase"

Class "uppercase" had been used to create visual hierarchy in backend
modules. Now we have H1-H6.

Resolves: #37925
Releases: master
Change-Id: I10eda8bb8a2d49f66c4d587e4cb35fc51be58712
Reviewed-on: http://review.typo3.org/32979
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
[TASK] Add empty extension compatibility6

This is a placeholder extension taking deprecated functionality
into child care to prolong the adaption phase for updating
individuals.
After all function have been moved, this extension will
be released to TER and removed from TYPO3 CMS core.

Change-Id: I8df0ecefcebdf3f2fe304529e6a79065254dee8e
Resolves: #62014
Relates: #62013
Releases: master
Reviewed-on: http://review.typo3.org/33127
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>
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>
[TASK] Improve namings of CheckboxElement

Use better namings for variables in CheckboxElement.

Count of selectedItems is done multiple times.
Better is to do the counting once and use the result in the
other places.

Resolves: #62012
Releases: master
Change-Id: Id0cced22902dafc33ef086a964e3f9a61891bff6
Reviewed-on: http://review.typo3.org/33122
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>