[TASK] Move t3lib/csconvtbl && t3lib/unidata

Move the 2 folders t3lib/csconvtbl && t3lib/unidata to
sysext/core/Resources/Private/Charsets/

Change-Id: If721bfe5ab7887f67ca774ae5a409d6f67ef009e
Resolves: #49005
Releases: 6.2
Reviewed-on: https://review.typo3.org/21326
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer