CI: Drop automation/configs/

CI: Drop automation/configs/

Having 3 extra hypervisor builds on the end of a full build is deeply
confusing to debug if one of them fails, because the .config file presented in
the artefacts is not the one which caused a build failure.  Also, the log
tends to be truncated in the UI.

PV-only is tested as part of PV-Shim in a full build anyway, so doesn't need
repeating.  HVM-only and neither appear frequently in randconfig, so drop all
the logic here to simplify things.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 7b20009a812f26e74bdbde2ab96165376b3dad34)