All enabled tests are now true unit tests with no external dependencies; new `requirements.txt` file in `test/` that installs testing requirements (`pytest`, `pytest-mock`, etc.); and `run-tests.sh` now has an extra step that installs these

This reverts commit 4ca7d034.

This reverts commit 76077477.

SSA-6324: schema init adds convenience methods suggested by Thomas; Project how has authors cascade; deploy requires Python 3.8; a project updater test now requires pytest-mock; updater and datafetcher tests complete, and most exercise CLI

Implemented parsing of setup.py files within a buildout recipe; next is to generate meta.yaml files for each setup file parsed