Refactor the way Elastic client is being setup

[pkarw]

Currently, we have have a code duplication with Elastic:

• migrations/.common.js
• platform/magento1/tax.js
• platform/magento2/tax.js

we should extract the Elastic client setup code to ../../helpers/elastic.js

kind of:

	const getElasticClient = (config) => {
        const esConfig = { // as we're runing tax calculation and other data, we need a ES indexer
          host: {
            host: config.elasticsearch.host,
            port: config.elasticsearch.port,
            protocol: config.elasticsearch.protocol
          },
          apiVersion: config.elasticsearch.apiVersion,
          requestTimeout: 5000
        }
        if (config.elasticsearch.user) {
          esConfig.httpAuth = config.elasticsearch.user + ':' + config.elasticsearch.password
        }
        return new es.Client(esConfig)	
	}

[simonmaass]

@pkarw is this deployed? If i look into current deployment i see that it doesnt use the protocol...

const esConfig = { // as we're runing tax calculation and other data, we need a ES indexer
host: this._config.elasticsearch.host + ':' + this._config.elasticsearch.port,
log: 'debug',
apiVersion: this._config.elasticsearch.apiVersion,
requestTimeout: 5000
}

[pkarw]

@simonmaass please do check the develop branch