* 10631: Get CircleCI to store Python coverage report
* 10631: Ensure coverage config file is copied into Docker container
..so that artefacts end up in the expected place for downstream processing
* 10631: Copy the coverage report to the CI host so it can be collected as an artefact
* 10631: Support CodeCov reporting
This changeset makes Bedrock tests use coverage.py once more, but this time via the pytest-cov plugin
The configuration set up ignores a (seemingly) sensible set of files and folders, while also outputting HTML and XML reports, for human and [future] machine enjoyment.
Key changes:
* Config expanded for coverage.py
* Main test-running script updated to invoke pytest with the appropriate coverage-logging options
* Docs updated with a small note.