Fixing and improving some paths and logistics for corrections, e.g. scale and smearing

HiggsDNA now runs when doing the chain

cd scripts
python pull_files.py --all # needs eos
<do your analysis with systematics and whatever corrections you pulled>

So harmonised the paths to store systematic JSONs in higgs_dna/systematics instead of all over the place (except goldenJSON which is not a systematic and not even a real correction, that is placed in metaconditions)