add steamcmd login to loserver cfg

lgsm/config-default/config-lgsm/loserver/_default.cfg

@@ -8,6 +8,10 @@
 
 #### Game Server Settings ####
 
+## SteamCMD Login | https://docs.linuxgsm.com/steamcmd#steamcmd-login
+steamuser="username"
+steampass='password'
+
 ## Predefined Parameters | https://docs.linuxgsm.com/configuration/start-parameters
 servername="LinuxGSM"
 ip="0.0.0.0"