File Support

Ticket moved to GitHub: "pulp/pulp_file/615":https://github.com/pulp/pulp_file/issues/615

The File Remote accepts a 'proxy_url' parameter[0]. When set, the File Remote uses the proxy for all requests during a sync operation.

This test will require writing a very simple server using aiohttp[1] that will proxy all requests and log them in such a way that pulp-smash can read the log. The test needs to do the following:

1. Start the proxy service on port 12345
2. Create a repository
3. Create a remote with a proxy_url set to 'localhost:12345'
4. Create a repository version by syncing from the Remote.
5. Assert that the proxy service received all the requests from Pulp.
6. Assert the sync was successful.

[0] https://docs.pulpproject.org/en/3.0/nightly/restapi.html#operation/remotes_file_file_create