[!!!][TASK] Move old legacy content objects to compatibility6

The following content objects are moved to
EXT:compatibility6, as they are considered
not state-of-the-art anymore.

 * CTABLE
 * OTABLE
 * HRULER
 * CLEARGIF
 * COLUMNS

They are not used inside the core anymore.

Resolves: #64639
Releases: master
Change-Id: I8e4a04997e2f7edff0ebeb8801158cf381dec06a
Reviewed-on: http://review.typo3.org/36426


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Jan Helke <typo3@helke.de>
Tested-by: Jan Helke <typo3@helke.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>