Remove proxy configuration from environment

All machines have now direct connection with the outside world.

Reviewed-by: Aleix Boné <abonerib@bsc.es>

m/common/ssf/net.nix

@@ -9,14 +9,6 @@
     defaultGateway = "10.0.40.30";
     nameservers = ["8.8.8.8"];
 
-    proxy = {
-      default = "http://hut:23080/";
-      noProxy = "127.0.0.1,localhost,internal.domain,10.0.40.40,hut";
-      # Don't set all_proxy as go complains and breaks the gitlab runner, see:
-      # https://github.com/golang/go/issues/16715
-      allProxy = null;
-    };
-
     firewall = {
       extraCommands = ''
         # Prevent ssfhead from contacting our slurmd daemon