Add a test to ensure FileRemote with client_cert and client_key configured can sync from a protected repository

[pulpbot]

Author: @bmbouter (bmbouter)

Redmine Issue: 6810, https://pulp.plan.io/issues/6810

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It's possible to have a Pulp Remote, e.g. FileRemote sync from a CertGaurd protected repo. This should work with either RHSM or X509 Certificate as long as the header is right.

We need to add a test that does the following:

Setup parts of the test

1. Create a FileRepository and sync some content into it
2. Create a Publication from (1) and serve it at a FileDistribution

Test sync when it's unprotected

3. Create a FileRemote and a second repository and sync the FileDistribution from (2) with it

Test sync fails against protected repo without cert_key and client_key

4. Protect this content with an X509 certificate
5. Try to sync the second repo using the FileRemote and assert that it fails with a 403 error (because the FileRemote has no client_cert and client_key)

Test sync works when FileRemote has client_cert and client_key

6. Add the client_cert and client_key to the FileRemote from (3)
7. Sync the second repo once more and assert it passes