message: Add deprecation warning for application.showHackingInstructor property
diff: @@ -15,6 +15,9 @@ const validateConfig = ({ products = config.get('products'), exitOnFailure = tru
  success = checkThatThereIsOnlyOneProductPerSpecial(products) && success
  success = checkThatProductArentUsedAsMultipleSpecialProducts(products) && success
  + if (config.has('application.showHackingInstructor')) { // TODO Remove fallback with v10.0.0
  + logger.info(`Configuration ${colors.bold(process.env.NODE_ENV || 'default')} defines deprecated ${colors.yellow('application.showHackingInstructor')}! Please use ${colors.bold('hackingInstructor.isEnabled')} instead.`)
  + }
  if (success) {
  logger.info(`Configuration ${colors.bold(process.env.NODE_ENV || 'default')} validated (${colors.green('OK')})`)
  } else {
  