[CLEANUP] TSFE: Deprecate JSfuncCalls for body tag

For old systems without proper JS libraries or usages like GMENU_LAYERS
TSFE provides an array to register handlers directly that are added
to the body tag directly.

This function is removed (only used for GMENU_LAYERS) from the core,
as all according functions should do this via hook or JS-only.

Resolves: #62363
Releases: master
Change-Id: I746e27c88c372dce61dadb6025d9348d34566fdf
Reviewed-on: http://review.typo3.org/33403
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>