Add storage class to the json input file of the cta-change-storage-class tool

When changing cta-change-storage-class by removing gRPC, we will now instead have the tool cta-change-storage-class-in-catalogue. As this tool should update the catalogue according to the dump it gets from the eos host, it is possible that these eos files have different storage classes. We should therefore update the input of cta-change-storage-class-in-catalogue so that it has the field storageclass:

{ "archiveId": <archiveId>, "fid": <fid>, "instance": <instance>, "storageclass": <storageclass> }