Update README section on policy output format

Need to update documentation on how the raw logs are stored to match our current organization scheme (see below)

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└── list-policy_<device>_<policy>_slurm-<jobid>_<rundatetime>/
    ├── raw/
    │   └── list-policy_<device>_<policy>_slurm-<jobid>_<rundatetime>.gz
    ├── chunks
    ├── parquet
    └── reports