Adding two helper scripts to unpack cloud-config-novajoin.json to a more
readable form. After editing cloud-config-novajoin.yaml, it still has to
be packed into cloud-config-novajoin.json with tools/cloud-config-pack.py.
Related-Bug: 1836529
Change-Id: I3d6a3e5f97608f7f8a0070f40ddeb8a7113c33b3
Mostly negative testing. There is a single positive test which can
still succeed even if IPA is not configured due to the imports test
in novajoin/ipa.py.