fix: Whitelist cli args

[amaury1093]

fix #550

Only two flags possible:

• --chain
• --no-run-parity: kept this one, iirc was requested a couple of times in parity ui, and harmless

Any other flags will exit Fether with error code != 0.

[axelchalon]

My hunch is that Electron or MacOs would be pass down flags to Electron, which are unexpected on our side and would make the program exit with error code != 0 (because we don't allow unknown arguments anymore). I think I would keep the filtering of process.argv ?

parse(
    process.argv
      // We want to ignore some flags and not pass them down to Parity:
      // --inspect: `electron-webpack dev` runs Electron with the `--inspect` flag for HMR
      // -psn_*: https://github.com/paritytech/fether/issues/188
      // --ws-interface: we don't pass down this flag, because fether only allows 127.0.0.1 as WS interface
      .filter(
        arg =>
          !arg.startsWith('--inspect') &&
          !arg.startsWith('-psn_') &&
          !arg.startsWith('--ws-interface')
      )

[amaury1093]

It seems that --inspect is not passed by electron-webpack anymore, so we can remove that one. --ws-interface has been removed.

You're probably right, i'll keep arg => !arg.startsWith('-psn_') just to be sure

[Tbaut]

tested with yarn electron --chain kovan successfully.