HostDisplay: Add threaded presentation for Vulkan renderer

Can add a significant speedup for fast forward. Automatically disabled
when vsync is enabled.

src/core/settings.h

@@ -97,6 +97,7 @@ struct Settings
   u32 gpu_resolution_scale = 1;
   u32 gpu_multisamples = 1;
   bool gpu_use_thread = true;
+  bool gpu_threaded_presentation = true;
   bool gpu_use_debug_device = false;
   bool gpu_per_sample_shading = false;
   bool gpu_true_color = true;