Add coverage profile to test commands

[dgannon991]

What does this change

Adds code coverage output to Unit & Integration test commands

What issue does it fix

Closes #372

Notes for the reviewer

The issue mentions that someone else will need to enable the code coverage tool on the pipeline.

Checklist

• Did you write tests?
• Did you write documentation?
• Did you change porter.yaml or a storage document record? Update the corresponding schema file.
• If this is your first pull request, please add your name to the bottom of our Contributors list. Thank you for making Porter better! 🙇‍♀️

Reviewer Checklist

• Comment with /azp run test-porter-release if a magefile or build script was modified
• Comment with /azp run porter-integration if it's a non-trivial PR

[schristoff]

Thank you so much! 😊