Add TestImageWithStorageNetwork

[albinsun]

Which issue(s) this PR fixes:

Issue harvester/tests#1083

What this PR does / why we need it:

1. Add test_1_images.py::TestImageWithStorageNetwork to test image operations within storage-network context, includes:
   • create_image_by_file
   • download_image
   • delete_image
2. Set raise_on_status=False on session retry_strategy to let requests return 5XX response instead of Max retries exceeded ... error for handy testing.
   • https://urllib3.readthedocs.io/en/stable/reference/urllib3.util.html#urllib3.util.Retry
   • https://stackoverflow.com/questions/54356759/python-requests-how-to-determine-response-code-on-maxretries-exception

Special notes for your reviewer:

1. Use small size fake_image_file fixture to test both upload and download quickly.

Additional documentation or context

Positive Tests

• v1.2.2 w/ -k test_1_image (build harvester-runtests/40)
• v1.2.2 w/ -k test_0 or test_1 (build harvester-runtests/41)

Negtive Tests

• v1.2.1 w/ -k test_0 or test_1_image (local build, can catch fail)