[TASK] Replace lowercase constant names with uppercase

I skipped the PHP Parser library in Resources/Private
since it will be easier to compare the code in case
of an update

Resolves: #58228
Releases: 6.2

Change-Id: If5e7be749aa581058f0a57ac8e5b2f9e7f45b8af
Reviewed-on: https://review.typo3.org/29757
Reviewed-by: Stefan Neufeind
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen