ci: Rework installed tests to use Fedora Standard Test interface

ci: Rework installed tests to use Fedora Standard Test interface

Reusing the way `standard-test-roles` has support for booting
a qcow2 actually gets us to the "VM-in-container" flow.  Plus
Ansible over shell script is sometimes nicer.

https://fedoraproject.org/wiki/CI/Tests#Testing_an_Atomic_Host

It's better than what we were doing before for installed tests,
and moreover using Ansible more broadly for testing is going
to align us better with Fedora's CI.

As part of this I split off a "libpaprci" which I intend to maintain
as a "copylib" for a little bit between ostree/rpm-ostree, and then
we'll figure out how to expand from there (maybe some of the patterns
get "baked in" to PAPR for example).

Note the `FAH27-insttests` context moves to the top since it's now
of primary importance, and I expect that we start expanding it.

Closes: #1462
Approved by: jlebon