feat (csgoserver): add Danger Zone game mode example (#2095)

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

@@ -10,14 +10,15 @@
 
 ## Server Start Settings | https://github.com/GameServerManagers/LinuxGSM/wiki/Start-Parameters
 # https://developer.valvesoftware.com/wiki/Counter-Strike:_Global_Offensive_Dedicated_Servers#Starting_the_Server
-# [Game Modes]			gametype	gamemode	mapgroup (you can mix these across Game Modes, but use only one)
-# Arms Race				1			0			mg_armsrace
-# Classic Casual		0			0			mg_casualsigma, mg_casualdelta
-# Classic Competitive	0			1			mg_active, mg_reserves, mg_hostage, mg_de_dust2
-# Custom				3			0
-# Deathmatch			1			2			mg_deathmatch
-# Demolition			1			1			mg_demolition
-# Wingman				0			2			
+# [Game Modes]					gametype	gamemode	mapgroup (you can mix these across Game Modes, but use only one)
+# Arms Race						1			0			mg_armsrace
+# Classic Casual				0			0			mg_casualsigma, mg_casualdelta
+# Classic Competitive			0			1			mg_active, mg_reserves, mg_hostage, mg_de_dust2
+# Custom						3			0
+# Deathmatch					1			2			mg_deathmatch
+# Demolition					1			1			mg_demolition
+# Wingman						0			2			
+# Danger Zone (FreeForAll)		6			0			mg_dz_blacksite
 gametype="0"
 gamemode="0"
 mapgroup="mg_active"