re-add FROMURL example for Suricata in compose files

docker/suricata/docker-compose.yml

@@ -10,6 +10,8 @@ services:
     environment:
     # For ET Pro ruleset replace "OPEN" with your OINKCODE
      - OINKCODE=OPEN
+    # Loading externel Rules from URL 
+    # - FROMURL="https://username:password@yoururl.com|https://username:password@otherurl.com"
     network_mode: "host"
     cap_add:
      - NET_ADMIN