Move testdata tarball into this repo
    
    Again to reduce direct usage of pagure.io, move the testdata
    tarball (used by download_testdata) directly into this repo. For
    now it includes repository.tar.gz, which is silly, but I'll send
    a follow-up PR to openqa_testdata to drop that file if this works
    out. This includes a script to produce the tarball from the base
    repository, and adjusts download_testdata to get the tarball from
    autoinst_url and update its unpacking logic (as this version of
    the tarball has a top-level directory).
    
    Note the tarball in this commit is actually from the branch that
    backs https://pagure.io/fedora-qa/openqa_testdata/pull-request/1
    to reduce size.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>