[Nantes] add cooling system metrics

data/grid5000/sites/nantes/pdus/cooling-Z1.json

data/grid5000/sites/nantes/pdus/pdu-Z1.10.json

data/grid5000/sites/nantes/pdus/pdu-Z1.11.json

data/grid5000/sites/nantes/pdus/pdu-Z1.20.json

data/grid5000/sites/nantes/pdus/pdu-Z1.21.json

data/grid5000/sites/nantes/pdus/pdu-Z1.40.json

data/grid5000/sites/nantes/pdus/pdu-Z1.41.json

data/grid5000/sites/nantes/pdus/pdu-Z1.50.json

data/grid5000/sites/nantes/pdus/pdu-Z1.51.json

input/grid5000/sites/nantes/pdus.yaml