VulkanDevice: Add TryImportHostMemory

Utilizing `VK_EXT_external_memory_host`, attempt to import the host-pointer into a `VkBuffer`, `VkDeviceMemory`, and an offset to the start of the data. When the page size matches the import alignment, then it is possible to import an entire range of memory from the host directly into a vulkan-side buffer to read and write into.

src/util/vulkan_device.h

@@ -341,6 +341,9 @@ private:
 
   void RenderBlankFrame();
 
+  bool TryImportHostMemory(const void* data, u32 data_size, VkBufferUsageFlags buffer_usage, VkDeviceMemory* out_memory,
+                           VkBuffer* out_buffer, u32* out_offset);
+
   bool CheckDownloadBufferSize(u32 required_size);
   void DestroyDownloadBuffer();