[all/servers] remove api-server-v4 virtual machines

data/grid5000/sites/grenoble/servers/api-server-v4.json

data/grid5000/sites/lille/servers/api-server-v4.json

data/grid5000/sites/lyon/servers/api-server-v4.json

data/grid5000/sites/nancy/servers/api-server-v4.json

data/grid5000/sites/nantes/servers/api-server-v4.json

data/grid5000/sites/rennes/servers/api-server-v4.json

data/grid5000/sites/sophia/servers/api-server-v4.json

input/grid5000/sites/grenoble/servers/virtual.yaml

input/grid5000/sites/lille/servers/virtual.yaml

input/grid5000/sites/lyon/servers/virtual.yaml

input/grid5000/sites/nancy/servers/virtual.yaml

input/grid5000/sites/nantes/servers/virtual.yaml

input/grid5000/sites/rennes/servers/virtual.yaml

input/grid5000/sites/sophia/servers/virtual.yaml