Add mocha-jenkins-reporter to stripes-cli to generate XML reports for mocha

We are currently publishing UI integration test reports in Jenkins by adding HTML tags around the default mocha output. I'd prefer to do away with this hack and generate XML-based reports that can be published with junit in Jenkins while still preserving the default mocha output to stdout. mocha-jenkins-reporter should do the trick.

https://www.npmjs.com/package/mocha-jenkins-reporter

The default JUNIT_REPORT_PATH should be set to 'artifacts/uitest/report.xml'