Test AM Vagrant box before publishing it

[replaceafill]

While testing #364 locally I noticed that the AM vagrant box build finishes successfully but the AM services do not start due to Python 3.9 missing.

The reason is this block in the clean up process:

# Delete development packages
dpkg --list \
    | awk '{ print $2 }' \
    | grep -- '-dev$' \
    | xargs apt-get -y purge;

That expression is too loose and it matches python3.9-dev among other important libraries for AM.

So, this adds steps to test the Vagrant box created through the Archivematica Vagrant box CI workflow.

In the commits of the pull request you can see how the new test fails in https://github.com/artefactual-labs/am-packbuild/tree/b4c7fb99e81ff20e92c4bcf42a657d569d1206d0 because Python 3.9 has been deleted:

Then after removing the block from the clean up file above the test passes in https://github.com/artefactual-labs/am-packbuild/tree/32b3184a92f99c37228b64be2509987238e82a14.

I also split the workflow into two jobs, one for building the base image and one for building, testing and publishing the AM box image. This saves time if the AM box build fails but the base image has been created successfully and the workflow needs to be retried.

Connected to archivematica/Issues#1720