tmt/testing followups phase 2: flexible provisioning and build #1624
Description
Splitting out of #1473 where #1607 changes a lot of things but as always there's lots of followups.
This also relates to https://gitlab.com/fedora/bootc/tests/bootc-workflow-test/-/issues/361
Basically we support multiple provisioning systems (Anaconda, bib/to-disk, s-r-b). Our tests should support being run from any of these.
In this I think we can change our TMT logic to execute different prepare phases
[ ] Support a packit-based flow where packit builds an RPM and injects it into the target environment and then we just do FROM <base> RUN dnf -y upgrade bootc.rpm and then do a system-reinstall-bootc to that as a preparatory step
[ ] Support Anaconda
In the Anaconda flow we require a container image as input, and I'd really like to support that locally with libvirt without pushing to a registry, but also in the cloud.
Also, I need to publish "bcvk" (formerly bootc-kit) which already streamlines the local unprivileged to-disk flow and can be extended for local Anaconda and bib.