In order to avoid adding return variables for each value we want to
extract at migration time we are now collecting them in a result object.

This object could later be extended and reused for the inspect scripts
instead of using a map.

When migrating from a non-containerized server, the user may want to
setup confidential computing attestation.

Using podman creds is not secure as those will show up in the the ps output.
Instead we generate a temporary podman authentication file and pass it to
podman pull.

It doesn't make sense to try to extract all the values for both
containers and hosts. This commit introduces Inspector objects that are
responsible for generating the inspection script and parsing it into a
structure.

While at it, the extracted values that were not used have been removed.
This gains quite some time at each execution since extracting the
SCC registration status was quite long.

While doing this we could also drop the InspectData proxyHost flag as
SCC credentials are extracted for both server and proxy hosts.