message: billing - import cleanup
diff: import { BillingChargeInvoiceAction, BillingDataTransactionStart, BillingDataTransactionStop, BillingDataTransactionUpdate, BillingInvoice, BillingInvoiceItem, BillingInvoiceStatus, BillingOperationResult, BillingPaymentMethod, BillingStatus, BillingTax, BillingUser, BillingUserSynchronizeAction } from '../../types/Billing';
  -import FeatureToggles, { Feature } from '../../utils/FeatureToggles';
  import Transaction, { StartTransactionErrorCode } from '../../types/Transaction';
  import User, { UserStatus } from '../../types/User';
  @@ -14,7 +13,6 @@ import NotificationHandler from '../../notification/NotificationHandler';
  import { Promise } from 'bluebird';
  import { Request } from 'express';
  import { ServerAction } from '../../types/Server';
  -import SettingStorage from '../../storage/mongodb/SettingStorage';
  import Tenant from '../../types/Tenant';
  import TenantStorage from '../../storage/mongodb/TenantStorage';
  import TransactionStorage from '../../storage/mongodb/TransactionStorage';
  