[!!!][TASK] Remove ExtJS Debugging and $GLOBALS['error']

The global variable $GLOBAL['error'] is used only in ExtJS-context for ExtDirect
(via ExtDirectDebug) however, but evaluates at every request.

This is the first of a series of patches to remove ExtJS in total.

The global methods debugBegin() and debugEnd() are removed as well.

Resolves: #37180
Releases: master
Change-Id: I00843d85660e85c213ac66059abdd84344c4fe3f
Reviewed-on: https://review.typo3.org/53817


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>