Core/Game: Include cleanup

* Mostly aimed at removing Log/DatabaseEnv includes from other headers
* Fix most packet headers including other packet headers - moved common structures such as ItemInstance to their own files
* Moved SAI function definitions to source files (massive or requiring many different dependencies)

src/server/game/AI/ScriptedAI/ScriptedCreature.h

@@ -25,17 +25,6 @@
 #include "InstanceScript.h"
 #include "TaskScheduler.h"
 
-#define CAST_AI(a, b)   (dynamic_cast<a*>(b))
-#define ENSURE_AI(a,b)  (EnsureAI<a>(b))
-
-template<class T, class U>
-T* EnsureAI(U* ai)
-{
-    T* cast_ai = dynamic_cast<T*>(ai);
-    ASSERT(cast_ai);
-    return cast_ai;
-};
-
 class InstanceScript;
 
 class TC_GAME_API SummonList