Issue discard requests for free pool space (offline tool).

Usage: thin_trim [OPTIONS] --metadata-dev <FILE> --data-dev <FILE>

Options:
      --data-dev <FILE>      Specify the pool data device
  -h, --help                 Print help
      --metadata-dev <FILE>  Specify the pool metadata device
  -q, --quiet                Suppress output messages, return only exit code.
  -V, --version              Print version