[lille] add VM 'users-api-alpha'

data/grid5000/sites/lille/servers/users-api-alpha.json

+{
+  "alias": [
+    "ums"
+  ],
+  "kind": "virtual",
+  "network_adapters": {
+    "default": {
+      "ip": "172.16.47.147"
+    }
+  },
+  "type": "server",
+  "uid": "users-api-alpha"
+}