This reverts commit 68320db2.

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

Hopefully final changes to setup.py files regarding package name changes; renamed a amqp_helpers dir to channels

SSA-6324: tests pass when run locally; some fail in Docker container. Committing what I've got so as not to lose it after tearing my hair out for a day and a half.

SSA-6324: pytest on datafetcher_test.py executes in a Docker container. capo properties file is copied to the docker build directory, then deleted.

Tests all succeed when executed in IJ.

master: reorganized datafetcher "SDM-only" functionality removed. All tests pass, including those that launch DF from a process to simulate command-line execution. TODO: actual command line, as below, should work but doesn't yet:

datafetcher --profile local --output-dir ~/Downloads --product-locator uid://evla/execblock/93e1c0cd-76de-4e65-a3f2-d5fe55f386d8 --verbose

Pylint also finds some errors, the consequence of fixing which puts red ink in the IJ editor and causes the above-mentioned command-line tests to fail.