[grenoble] remove dahu cluster configuration

data/grid5000/sites/grenoble/clusters/dahu/dahu.json

data/grid5000/sites/grenoble/clusters/dahu/nodes/dahu-1.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-12.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-13.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-14.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-15.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-16.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-18.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-19.json

data/grid5000/sites/grenoble/clusters/dahu/nodes/dahu-2.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-20.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-21.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-22.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-23.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-24.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-25.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-26.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-27.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-28.json

.../grid5000/sites/grenoble/clusters/dahu/nodes/dahu-29.json