[TASK] Pretty print JSON

Releases: 6.2
Resolves: #49315
Change-Id: I3783797c4406515ec592028f34decded0b88112d
Reviewed-on: https://review.typo3.org/29736
Reviewed-by: Stefan Neufeind
Reviewed-by: Markus Klein
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen