Improve template comments

Author: ostefano

template.env

@@ -49,6 +49,7 @@ GPG_PASSPHRASE=
 # defaults to 1 (the admin user)
 CRON_USER_ID=
 # defaults to 'https://localhost'
+# note: if you are exposing MISP on a non-standard port (i.e., the port is part of the URL you would use to access it, e.g., https://192.168.0.1:4433) you need to include the port in the BASE_URL variable
 BASE_URL=
 # store settings in db except those that must stay in config.php. true/false, defaults to false
 ENABLE_DB_SETTINGS=