Fix python dockerpy tests

* Refactor packaging so unittest discovery works
* Refactor tests to use python3-docker.rpm that ships with Fedora32
* Flush image cache between tests suites
* Update documentation to reflect changes

Outstanding issue:
* client.get_image() does not fail if image does not exist

Signed-off-by: Jhon Honce <jhonce@redhat.com>

test/python/dockerpy/README.md

@@ -0,0 +1,40 @@
+# Dockerpy regression test
+
+Python test suite to validate Podman endpoints using dockerpy library
+
+## Running Tests
+
+To run the tests locally in your sandbox (Fedora 32):
+
+```shell script
+# dnf install python3-docker
+```
+
+### Run the entire test suite
+
+```shell
+# cd test/python/dockerpy
+# PYTHONPATH=/usr/bin/python python -m unittest discover .
+```
+
+Passing the -v option to your test script will instruct unittest.main() to enable a higher level of verbosity, and produce detailed output:
+
+```shell
+# cd test/python/dockerpy
+# PYTHONPATH=/usr/bin/python python -m unittest -v discover .
+```
+
+### Run a specific test class
+
+```shell
+# cd test/python/dockerpy
+# PYTHONPATH=/usr/bin/python python -m unittest -v tests.test_images
+```
+
+### Run a specific test within the test class
+
+```shell
+# cd test/python/dockerpy
+# PYTHONPATH=/usr/bin/python python -m unittest tests.test_images.TestImages.test_import_image
+
+```