Core/Achievements: AchievementMgr refactoring

* Extracted base CriteriaHandler class that deals with criteria only and will be reused for future scenario implementation
* Fixed players earning guild achievements

src/server/game/Maps/MapManager.cpp

@@ -34,7 +34,6 @@
 #include "Player.h"
 #include "WorldSession.h"
 #include "Opcodes.h"
-#include "AchievementMgr.h"
 #include "MiscPackets.h"
 
 MapManager::MapManager()
@@ -370,5 +369,4 @@ void MapManager::FreeInstanceId(uint32 instanceId)
         SetNextInstanceId(instanceId);
 
     _instanceIds[instanceId] = false;
-    sAchievementMgr->OnInstanceDestroyed(instanceId);
 }