Introducing Codecov.io for coverage reports and CI integration

[JunTaoLuo]

Description

Testing Codecov.io for our coverage reporting. Resolves #16136. Note that this is currently blocked on getting codecov github app installed and getting the right permissions and will not run correctly yet.

Testing done

In progress

Screenshots

QA steps

TBD

Definition of Done

• Documentation has been updated, if applicable.
• Tests have been added if necessary.
• Automated tests have passed.
• Code Quality Tests have passed.
• Acceptance Criteria in related issue are met.
• Manual Code Review Approved.
• If there are field changes, front end output has been thoroughly checked.

Select Team for PR review

• CMS Team
• Public websites
• Facilities
• User support
• Accelerated Publishing

[github-actions]

GitHub Workflows (.github/workflows/*.yml)

Have you...

• pinned all affected GitHub Actions at a specific commit by SHA?
• reviewed the source code of the action at the commit you are pinning?
• confirmed that no GitHub security measures are being bypassed?
• checked for any injection of user content into protected contexts?
• reviewed Security hardening for GitHub Actions?
• reviewed GitHub Workflows?

[JunTaoLuo]

We don't have the right permissions to install and test the app in this PR. Will discuss findings in linked issue.