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/scripts/Commands/cs_server.cpp

@@ -24,13 +24,14 @@ EndScriptData */
 
 #include "Chat.h"
 #include "Config.h"
+#include "GitRevision.h"
 #include "Language.h"
 #include "Log.h"
 #include "ObjectAccessor.h"
 #include "Player.h"
 #include "ScriptMgr.h"
-#include "GitRevision.h"
 #include "Util.h"
+#include "World.h"
 
 class server_commandscript : public CommandScript
 {