Make apex host specific to each machine

Allows direct contact via the VPN when accessing from fox, but use
Internet when using the rest of the machines.

Reviewed-by: Aleix Roca Nonell <aleix.rocanonell@bsc.es>

m/tent/configuration.nix

@@ -33,6 +33,9 @@
     nameservers = [ "84.88.52.35" "84.88.52.36" ];
     search = [ "bsc.es" "ac.upc.edu" ];
     defaultGateway = "10.0.44.1";
+    hosts = {
+      "84.88.53.236" = [ "apex" ];
+    };
   };
 
   services.p.enable = true;