Improve usage of std::move and const references parameters

Accomplished using `run-clang-tidy` with `performance-move-const-arg,performance-unnecessary-value-param,modernize-pass-by-value`.

Changed arguments to const references, removed them where inappropriate (e.g. sink parameters). Same with std::move.

Manually reviewed each change to make sure that it makes sense, and do something more appropriate if possible.

Source/Core/DolphinQt/GameList/GameList.h

@@ -56,7 +56,7 @@ signals:
   void GameCountUpdated(int total_games, int visible_games) const;
   void OnStartWithRiivolution(const UICommon::GameFile& game);
   void NetPlayHost(const UICommon::GameFile& game);
-  void SelectionChanged(std::shared_ptr<const UICommon::GameFile> game_file);
+  void SelectionChanged(const std::shared_ptr<const UICommon::GameFile>& game_file);
   void OpenGeneralSettings();
   void OpenGraphicsSettings();
 #ifdef USE_RETRO_ACHIEVEMENTS

Source/Core/DolphinQt/GameList/GameTracker.cpp

@@ -54,7 +54,7 @@ GameTracker::GameTracker(QObject* parent) : QFileSystemWatcher(parent)
   connect(&Settings::Instance(), &Settings::MetadataRefreshRequested, this,
           [this] { m_load_thread.EmplaceItem(Command{CommandType::UpdateMetadata, {}}); });
 
-  m_load_thread.Reset("GameList Tracker", [this](Command command) {
+  m_load_thread.Reset("GameList Tracker", [this](const Command& command) {
     switch (command.type)
     {
     case CommandType::LoadCache:
@@ -356,7 +356,7 @@ void GameTracker::LoadGame(const QString& path)
     bool cache_changed = false;
     auto game = m_cache.AddOrGet(converted_path, &cache_changed);
     if (game)
-      emit GameLoaded(std::move(game));
+      emit GameLoaded(game);
     if (cache_changed && !m_refresh_in_progress)
       m_cache.Save();
   }