cleanup(jafar): do not depend on netx and urlgetter (#792)

There's no point in doing that. Also, once this change is merged, it becomes easier to cleanup/simplify netx.

See https://github.com/ooni/probe/issues/2121

internal/cmd/jafar/iptables/iptables_integration_test.go

@@ -240,7 +240,7 @@ func TestHijackDNS(t *testing.T) {
 	}
 	resolver := resolver.NewCensoringResolver(
 		[]string{"ooni.io"}, nil, nil,
-		uncensored.Must(uncensored.NewClient("dot://1.1.1.1:853")),
+		uncensored.NewClient("https://1.1.1.1/dns-query"),
 	)
 	server, err := resolver.Start("127.0.0.1:0")
 	if err != nil {