[reims] Network_api - Rename s/gw/gw-reims (refs: #4867)

...grid5000/sites/reims/clusters/stremi/nodes/stremi-28.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-29.json

.../grid5000/sites/reims/clusters/stremi/nodes/stremi-3.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-30.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-31.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-32.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-33.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-34.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-35.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-36.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-37.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-38.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-39.json

.../grid5000/sites/reims/clusters/stremi/nodes/stremi-4.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-40.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-41.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-42.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-43.json

...grid5000/sites/reims/clusters/stremi/nodes/stremi-44.json

.../grid5000/sites/reims/clusters/stremi/nodes/stremi-5.json