Support for Visual Studio web performance and load tests.

[Results.zip](https://github.com/allure-framework/allure2/files/2241600/Results.zip)

#### I'm submitting a ...
- [ ] bug report
- [x] feature request
- [ ] support request => Please do not submit support request here, see note at the top of this template.

#### What is the current behavior?
It supports .trx files, but it does not support .trx files from VS web performance and load tests.

#### If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem
run a load tests form visual studio 2017.

#### What is the expected behavior?
Information from the test to appear in the Alurre2 report on Jenkins.

#### What is the motivation / use case for changing the behavior?
Mass load testing that is automated.

#### Please tell us about your environment:
Windows server 2016 Standard.
Jenkins with your plugin.
Visual Studio Enterprise 2017.

| Allure version | 2.2.0 |
| --- | --- |
| Test framework | testng@6.8 |
| Allure adaptor | allure-testng@2.0-BETA11 |
| Generate report using | allure-maven@2.18 |

#### Other information

[//]: # (
. e.g. detailed explanation, stacktraces, related issues, suggestions
. how to fix, links for us to have more context, eg. Stackoverflow, Gitter etc
)

Start with the supplied Results.zip and the existing .trx support, then compare the Visual Studio 2017 web performance and load test results with the format Allure currently accepts. Check the Jenkins report-generation path; done means information from these tests appears in the Allure2 report.

Written by the indexing model from the issue text.