Need a better structure for eval config files (yml), especially job_conf

[mosharaf]

It's completely flat structure under job_conf which makes it hard to follow and organize. A better hierarchical organization under this will allow us, for example, to separate aggregator-related params from worker-related ones; the same for job-related params from trace-related params; etc.

[mosharaf]

We should look into hydra (https://hydra.cc/)