[Rspamd, Postfix] Move PTR check to Postfix

data/conf/rspamd/local.d/hfilter_group.conf

@@ -0,0 +1,5 @@
+symbols = {
+    "HFILTER_HOSTNAME_UNKNOWN" {
+        score = 10.0;
+    }
+}

data/conf/rspamd/local.d/metrics.conf

@@ -26,6 +26,7 @@ group "MX" {
 	  one_shot = true;
 	}
 }
+
 symbol "CTYPE_MIXED_BOGUS" {
   score = 0.0;
 }