Provide a spec file for `image-builder-cli`. The spec file is based on
`osbuild-composer`'s spec file except it is simplified as (some)
usecases would currently cloud the intent of the specfile. We can add
back RHEL conditionals when/if we start shipping and building for RHEL.
Some tools from `osbuild-composer` are also included; most notably the
one that generates bundled dependencies from vendored modules.
Signed-off-by: Simon de Vlieger <supakeen@redhat.com>
