feat(worker/args): add basic command-line args parser

[lffg]

cargo run -p worker -- --help example output:

$ cargo run -p worker -- --help
    Finished dev [unoptimized + debuginfo] target(s) in 0.04s
     Running `target/debug/worker --help`
Usage: worker [OPTIONS] --controller-addr <CONTROLLER_ADDR>

Options:
  -c, --controller-addr <CONTROLLER_ADDR>
          Controller's HTTP address

      --metrics-report-interval <METRICS_REPORT_INTERVAL>
          Interval at which metrics are pushed to the controller.
          
          Time in seconds. Must be greater than 1.
          
          [default: 5]

  -h, --help
          Print help (see a summary with '-h')