Make the shader binding table reside in "device"-memory

[johannesugb]

The shader binding table (SBT) is created right after the ray tracing pipeline is created by the means of vk::Device::createRayTracingPipelineKHR and put into the following buffer:

result.mShaderBindingTable = create_buffer(
	memory_usage::host_coherent, 
	vk::BufferUsageFlagBits::eRayTracingKHR,				
	generic_buffer_meta::create_from_size(shaderBindingTableSize)
);

This has been done because then there needs to be no synchronization. However, host_coherent is suboptimal => it should be device-memory. In order to store the SBT-entries in device-memory, synchronization has to be added.