_ganacheCoreOptionsFromGanacheSettingsObject(settings) {
    // clone to avoid mutating the settings object in case it's sent elsewhere
    let options = cloneDeep(settings.server);

    if (settings.randomizeMnemonicOnStart) {
      delete options.mnemonic;
    }

    options.logDirectory = settings.logDirectory;

    return options;
  }
Returns an options object to be used by ganache-core from Ganache settings
model. Should be broken out to call multiple functions if it becomes even
moderately complex.