Random offset for DefaultGrid every round (#4411)

* Random offset for DefaultGrid every round

This is useful to make coders aware of entitycoordinates and mapcoordinates being different and to help spot problems early. It also puts the onus of fixing positioning bugs back onto the original coder rather than someone else if they happen to spot it.

* Fix clickable test

* Fix entitysystemextensions

Content.Shared/CCVar/CCVars.cs

@@ -55,6 +55,12 @@ namespace Content.Shared.CCVar
         public static readonly CVarDef<string>
             GameMap = CVarDef.Create("game.map", "Maps/saltern.yml", CVar.SERVERONLY);
 
+        /// <summary>
+        /// When the default blueprint is loaded what is the maximum amount it can be offset from 0,0.
+        /// </summary>
+        public static readonly CVarDef<float> MaxStationOffset =
+            CVarDef.Create("game.maxstationoffset", 1000.0f);
+
         /// <summary>
         ///     When enabled, guests will be assigned permanent UIDs and will have their preferences stored.
         /// </summary>