[qa] Avoid leaving test files after tests

[nemesifier]

Reserved for GCI

After running tests a test csv file is left on the filesystem.

• configure the settings.py test environment so that media files are uploaded to ./tests/media/
• add ./tests/media/* to .gitignore
• make sure ./tests/media/ is cleaned up during tearDown

[cking100]

@nemesisdesign could you please elaborate the 3rd point and what do you mean by teardown?

[nemesifier]

@cking100 https://docs.python.org/3/library/unittest.html#unittest.TestCase.tearDown