GHA: Configure workflows for reuse

It's possible to reuse a GHA workflow from another repo with minimal
YAML.  However there are certain requirements, like spelling out all the
required secret values.  Also any mention of `ACTIONS_STEP_DEBUG` will
cause failures and must be removed.

As usual, there's no convenient way to test these changes without pushing
to a `main` branch somewhere that also has all the proper secrets
configured.  However, I did pattern these changes off of a working setup
in buildah:

https://github.com/containers/buildah/blob/fd2d05c0a7ada9592e30a2eba941444b1d959ecf/.github/workflows/check_cirrus_cron.yml

Signed-off-by: Chris Evich <cevich@redhat.com>