Add DoState to AchievementManager

While state loading is not allowed in the hardcore mode that most players will use, it is allowed in softcore mode; more importantly, if something fails to unlock or unlocks when it shouldn't in either mode the player can create a save that retains the current achievement state.

Source/Core/Core/AchievementManager.h

@@ -148,6 +148,8 @@ public:
   const NamedIconMap& GetChallengeIcons() const;
   std::vector<std::string> GetActiveLeaderboards() const;
 
+  void DoState(PointerWrap& p);
+
   void CloseGame();
   void Logout();
   void Shutdown();