JUnit XML Test Results - MR Widget
### Description
When a `test` job fails in a pipeline, developers currently have to look into the job output log to diagnose which tests caused the failure. This can be time consuming analysis as there can be a lot of text to parse.
We can speed up the process by capturing the JUnit XML Output from the `test` job and displaying the errors directly in the MR widget.
### Priority Of JUnit XML Iterations
1. https://gitlab.com/gitlab-org/gitlab-ce/issues/45318 (MR Widget) JUnit Test Summary
1. https://gitlab.com/gitlab-org/gitlab-ce/issues/46563 (MR Widget) Display Which Tests Failed
1. https://gitlab.com/gitlab-org/gitlab-ce/issues/46564 (MR Widget) Link From Widget To Failed Testfile
1. https://gitlab.com/gitlab-org/gitlab-ce/issues/46565 (MR Widget) Display Stacktrace and System Out/Error Messages
1. https://gitlab.com/gitlab-org/gitlab-ce/issues/46566 (MR Widget) Display Failed Test Scenarios Comparing `Base` and `Head`
1. https://gitlab.com/gitlab-org/gitlab-ce/issues/46612 (MR Widget) Display Last Instance Test Failed
### See Also
https://gitlab.com/groups/gitlab-org/-/epics/384 (JUnit XML CI View)
epic