[!!!][TASK] Cleanup global debug functions

The global "xdebug()" function is removed, as it is a stub for "debug" nowadays.
This function exists since SVN days,  and no comment or change why this is
available.

Additionally, the global "debug()" function had 6 parameters - the last three
were not evaluated and thus, were removed.

Resolves: #82640
Releases: master
Change-Id: I3e583c06282842e3dcb14f4b68589fd706be2519
Reviewed-on: https://review.typo3.org/54256


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>