[TASK] Cleanup DebugUtility

The debug utility outputs JavaScript, even when in CLI mode.
Additionally all strings are not correctly encoded for
JavaScript.

Additionally deprecate the method which does incomplete encoding.

Releases: 6.0
Resolves: #42611

Change-Id: I68fadc5d8f10e967913d1b79bc7758a5a18d77f6
Reviewed-on: http://review.typo3.org/16117
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel