[Rspamd] Prepare SMTP ip restriction, WIP

data/conf/rspamd/local.d/multimap.conf

@@ -165,3 +165,9 @@ URLHAUS_ABUSE_CH {
   map = "https://urlhaus.abuse.ch/downloads/text_online/";
   score = 10.0;
 }
+
+SMTP_LIMITED_ACCESS {
+  type = "user";
+  map = "redis://SMTP_LIMITED_ACCESS";
+  symbols_set = ["SMTP_LIMITED_ACCESS"];
+}