[Kernel] Implemented Game Info Database

This aggregates XDBF and XLAST into one entity.

Replaced UserData::Key into more versatile AttributeKey for future usage in properties

src/xenia/emulator.h

@@ -20,6 +20,8 @@
 #include "xenia/base/delegate.h"
 #include "xenia/base/exception_handler.h"
 #include "xenia/kernel/kernel_state.h"
+#include "xenia/kernel/util/game_info_database.h"
+#include "xenia/kernel/util/xlast.h"
 #include "xenia/memory.h"
 #include "xenia/patcher/patcher.h"
 #include "xenia/patcher/plugin_loader.h"
@@ -318,6 +320,7 @@ class Emulator {
   kernel::object_ref<kernel::XThread> main_thread_;
   kernel::object_ref<kernel::XHostThread> plugin_loader_thread_;
   std::optional<uint32_t> title_id_;  // Currently running title ID
+  std::unique_ptr<kernel::util::GameInfoDatabase> game_info_database_;
 
   bool paused_;
   bool restoring_;