Refactored Achievement Mananger to load games through rc_client

HashGame has become LoadGame, similar structure with the file loaders but using the client instead. LoadGameCallback has been created to handle the results. The old LoadGameSync has been deleted as have
several hash and load methods that it called.

Source/Core/Core/Boot/Boot.cpp

@@ -576,8 +576,7 @@ bool CBoot::BootUp(Core::System& system, const Core::CPUThreadGuard& guard,
       }
 
 #ifdef USE_RETRO_ACHIEVEMENTS
-      AchievementManager::GetInstance().HashGame(executable.path,
-                                                 [](AchievementManager::ResponseType r_type) {});
+      AchievementManager::GetInstance().LoadGame(executable.path, nullptr);
 #endif  // USE_RETRO_ACHIEVEMENTS
 
       if (!executable.reader->LoadIntoMemory(system))