✨ [pi4] Added initial Simple mailserver config

hosts/pi4/forgejo.nix

@@ -34,9 +34,10 @@ in
         # Sending emails is completely optional
         # You can send a test email from the web UI at:
         # Profile Picture > Site Administration > Configuration >  Mailer Configuration
-        mailer = {
+        mailer = lib.mkIf config.mailserver.enable {
           ENABLED = true;
-          SMTP_ADDR = "mail.${common.domain}";
+          PROTOCOL = "smtps";
+          SMTP_ADDR = config.mailserver.fqdn;
           FROM = "noreply-forgejo@${common.domain}";
           USER = "noreply@${common.domain}";
         };