Adding support for container embedding.
The containers need to be specified in the image function (imageFunc)
arguments and when specified, propagate down to the OS pipeline
generator to add the necessary stages.
Support is added for RHEL 9.x and Fedora.
Requires a temporary container spec array with the info from the
blueprint for the first initialization of the manifest that's needed
when collecting required packages.
This should be simplified in the future.
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