Adds an option to destroy Vulkan old swapchain before

Now it's possible to destroy the old swapchain before creating a new
one. It might make the swapchain creation a bit slower but with a
lower memory peak.

source/renderer/backend/vulkan/Device.cpp

@@ -1039,6 +1039,13 @@ void CDevice::RecreateSwapChain()
 	{
 		vkDeviceWaitIdle(m_Device);
 
+		// It seems some drivers might not reuse the same swapchain memory. So
+		// to avoid higher memory peaks destroy the old swapchain before.
+		const bool destroyOldSwapchainBefore{
+			g_ConfigDB.Get("renderer.backend.vulkan.destroyoldswapchainbefore", false)};
+		if (destroyOldSwapchainBefore)
+			m_SwapChain.reset();
+
 		m_BackbufferReadbackTexture.reset();
 
 		// Since we know there is no GPU work in progress we can free resources