[x] Create conda env inside CI/CD and install psi4 for unit and integration tests.
[x] Install ROSE and run for unit and integration tests.
[x] ~Install DIRAC and run for unit and integration tests~ (I have prepared the workflow but because it takes a long time to compile it is currently commented out).
[x] Add workflow status badge
[x] ~Add code coverage badge~ (@NicoRenaud this requires public repos and repo_token addition; see here. Task postponed)
[x] ~Include "nightly builds" in CI/CD~ (included automatic build every two days at midnight)
This PR addresses #48
Tasks to do