Add Allure test report

[eduardoboucas]

It could be nice to generate Allure reports from our end-to-end test suite.

https://codecept.io/plugins#allure
https://demo.qameta.io/allure/#

(cc @davidmacp)

[davidmacp]

👀

[davidmacp]

I can get the tests to generate an allure report locally (somewhat basic at the moment but should be able to configure it to display as we want). However to view it, it is served up by a command-line tool that uses java (https://www.npmjs.com/package/allure-commandline). So not sure if that can be run through travis-ci? or how we could do that?