Revert "[TASK] Create new processor registry"

This reverts commit 07714455

This new interface is not being used throughout the Core,
as this was just the first step of three to complete this
functionality. So we revert and postpone this change for
the next release.

Change-Id: I5dd0e074a0026ff49b1d096ff4fd8926370aba3f
Reviewed-on: https://review.typo3.org/28598
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny