Refactored some exchange code

lib/plugins/exchange/kraken.js

@@ -0,0 +1,21 @@
+const common = require('../common/ccxt')
+const _ = require('lodash/fp')
+const consts = require('./consts')
+const ORDER_TYPE = consts.ORDER_TYPES.MARKET
+const FIAT = common.FIAT['kraken']
+const CRYPTO = common.CRYPTO['kraken']
+
+const loadConfig = (account) => {
+  const mapper = {
+    'privateKey': 'secret'
+  }
+  const mapped = _.mapKeys(key => mapper[key] ? mapper[key] : key)(account)
+  return { ...mapped, timeout: 3000 }
+}
+
+const loadOptions = () => ({ expiretm: '+60' })
+const isConfigValid = ({ apiKey, privateKey }) => apiKey && privateKey
+
+const amountPrecision = () => 6
+
+module.exports = { amountPrecision, loadOptions, loadConfig, isConfigValid, CRYPTO, FIAT, ORDER_TYPE }