HEPiX benchmarking solution for WLCG computing resources

<!--HTML-->The HEPiX Benchmarking Working Group has been developing a benchmark based on actual software workloads of the High Energy Physics community. This approach, based on container technologies, is designed to provide a benchmark that is better correlated with the actual throughput of the experiment production workloads. It also offers the possibility to separately explore and describe the independent architectural features of different computing resource types. This is very important in view of the growing heterogeneity of the HEP computing landscape, where the role of non-traditional computing resources such as HPCs and GPUs is expected to increase significantly.