break out whitebox tests

move whitebox tests to their own directory, with rules around
them. We had only a small number of tests here, and we don't
currently run these in gate, so these aren't added to tox.ini yet.

Part of bp:tempest-repo-restructure

Change-Id: Ic1d2158cd92d13ae25f026289f680396aa0ec3a8
6 files changed