Scripts/ZulFarrak: Convert Witch Doctor Zum'rah from SAI to Cpp

Closes #10508

src/server/game/Scripting/ScriptLoader.cpp

@@ -342,6 +342,7 @@ void AddSC_wailing_caverns();                //Wailing caverns
 void AddSC_instance_wailing_caverns();
 void AddSC_zulfarrak();                     //Zul'Farrak generic
 void AddSC_instance_zulfarrak();            //Zul'Farrak instance script
+void AddSC_boss_zum_rah();
 
 void AddSC_ashenvale();
 void AddSC_azshara();