Set the value of gitreview.username from the gerrit push URL

[harriebird]

Proposed changes

This will automatically get the username from the push URL when using Gerrit as VCS This solves issue #10596

Checklist

• [ ] Lint and unit tests pass locally with my changes.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added documentation to describe my feature.
• [ ] I have squashed my commits into logic units.
• [ ] I have described the changes in the commit messages.

Other information