Fixed some issues with PR #14157, kudos to @Nyeriah @Warpten:

* Moved scripts to other source file instead of having them on the instance cpp
* Removed magic number, use of DoAction instead of SetData to do the yelling
* Added spellscript for Remove Kargath's Executioner
* Saved victim GUIDs in instance script instead of checking nearby area
* Returning position as const-reference (by Naios)

src/server/game/Scripting/ScriptLoader.cpp

@@ -622,6 +622,7 @@ void AddSC_instance_magtheridons_lair();
 void AddSC_boss_grand_warlock_nethekurse();  //HC Shattered Halls
 void AddSC_boss_warbringer_omrogg();
 void AddSC_boss_warchief_kargath_bladefist();
+void AddSC_shattered_halls();
 void AddSC_instance_shattered_halls();
 void AddSC_boss_watchkeeper_gargolmar();     //HC Ramparts
 void AddSC_boss_omor_the_unscarred();
@@ -1152,6 +1153,7 @@ void AddOutlandScripts()
     AddSC_boss_grand_warlock_nethekurse();  //HC Shattered Halls
     AddSC_boss_warbringer_omrogg();
     AddSC_boss_warchief_kargath_bladefist();
+    AddSC_shattered_halls();
     AddSC_instance_shattered_halls();
     AddSC_boss_watchkeeper_gargolmar();     //HC Ramparts
     AddSC_boss_omor_the_unscarred();