Problem: CI builds do not provide test coverage metrics

[replaceafill]

Expected behaviour

The CI builds of all Archivematica related repositories provide test coverage metrics that help developers understand the impact of their code changes.

Current behaviour

Currently, only the mets-reader-writer repository stores and displays test coverage metrics through https://coveralls.io and shows a coverage badge in its README file in GitHub.

Alternatively, a3m, enduro and scope use https://codecov.io and also display coverage badges in their README files.

Steps to reproduce

See the CI build history of all the repositories we updated to use GitHub Actions in https://github.com/archivematica/Issues/issues/1329 or check that their README files don't display test coverage badges in GitHub.

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For Artefactual use:

Before you close this issue, you must check off the following:

• [ ] All pull requests related to this issue are properly linked
• [ ] All pull requests related to this issue have been merged
• [ ] A testing plan for this issue has been implemented and passed (testing plan information should be included in the issue body or comments)
• [ ] Documentation regarding this issue has been written and merged (if applicable)
• [ ] Details about this issue have been added to the release notes (if applicable)

[sevein]

+1 to codecov.io from @jraddaoui and me!