Switch tests to pytest and ansible-test.

- Replace nose usage with pytest.
- Remove legacy Shippable integration.sh.
- Update Makefile to use pytest and ansible-test.
- Convert most yield unit tests to pytest parametrize.

test/utils/tox/requirements-py3.txt

@@ -13,3 +13,4 @@ python3-memcached
 python-systemd
 botocore
 boto3
+pytest

test/utils/tox/requirements.txt

@@ -14,3 +14,4 @@ python-systemd
 pycrypto
 botocore
 boto3
+pytest