Compare different models for the same dataset

[aarora79]

There is nothing in FMBench which prevents different experiments in the same config file to use different models, but the generated report is not architected in the same way i.e. it is not created to compare different models but rather compare the same model across serving stacks, so that would need to change. This has been requested by multiple customers, the idea being if we find different models that are fit for task, we now want to find the model and serving stack combination which provides the best price:performance.