[nancy][server][viabaca] Add Viabaca VM description

data/grid5000/sites/nancy/servers/viabaca.json

+{
+  "kind": "virtual",
+  "network_adapters": {
+    "default": {
+      "ip": "172.16.79.136"
+    }
+  },
+  "type": "server",
+  "uid": "viabaca"
+}
\ No newline at end of file

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

@@ -163,3 +163,9 @@ guix:
   network_adapters:
     default:
       ip: 172.16.79.135
+viabaca:
+  kind: virtual
+  network_adapters:
+    default:
+      ip: 172.16.79.136
+