[CLEANUP] ClassLoader

Add methods to better structure class information loading/creation.
This is necessary as the follow up patches will need this code
more often.

Resolves: #56797
Releases: 6.2
Change-Id: I1f15fbd262036b6b2d0159cd0e9613ad7135a296
Reviewed-on: https://review.typo3.org/28279
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter
Reviewed-by: Sebastian Fischer
Reviewed-by: Patrick Broens
Tested-by: Patrick Broens