SSA-6324: refactored prop setter for testability and created tests; added script to run all tests in data repo

SSA-6324: Tests are tightened up and more efficient; pylint is (somewhat) mollified; optimizing them flushed out a bug or two in the updater.

SSA-6324: datafetcher tests proceed as expected in IJ and at command line, but not in Docker container. scode_updater tests proceed as expected in IJ, but not at the command line or in Docker container. Requirements updated; convenience script added for rebuilds.

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

SSA-6324: rearranged scode_project_updater package structure; started creating unit tests that don't depend on a particular state of the dev database

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