[CLEANUP] Drop the ClassParser class

This class is not used anymore and can be removed.

Change-Id: If7b90624c67c56129256eea79d487fe2ad673011
Resolves: #58252
Releases: 6.2
Reviewed-on: https://review.typo3.org/29685
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen