New feature - Add basic support for JUnit reports

[scyzoryck]

Hello! I would like to add some basic support for JUnit reports - that becomes a nice standard for the showing reports from tests in tools like gitlab or junit. Here is some MVP PR for the basic support to show basic information about failed or passed tests. Supported features:

• amount of executed scenarios (test suites) and steps (test cases)
• failure and error messages in report Result has been checked agains Jenkins schema.

Features that can be added in the future:

• better naming - right now it shows raw scenario names - without resolved variables.
• add time to the results

[lolautruche]

Thanks @scyzoryck ! LGTM