[X-POST] Script to convert Fedora Cloud instance to Fedora Server instance

[Haïkel]

Works for me, I like the fact that the script is limited to Python
standard library not to add new dependencies.

Few considerations:
1. there were some discussions about dropping Python from the base
cloud image. The rationale was to get the smallest viable image for
most usage, not everyone uses Python.
There are two blockers: cloud-init (could be replaced by
min-cloud-agent), yum (could be replaced by a libhif-based alternative
or already replaced by rpm-ostree/docker in the Atomic image)
Note that we could provide different image flavours including one with Python.
2. If we're gonna use yum/dnf, I suggest using the API
https://github.com/fedora-cloud/cloudtoserver/pull/2
3. I don't like hard-coding packages to be installed/removed/etc ...
in the script. I suggest that we use a configuration file, could be
shipped in the package or retrieved online (if you have no network,
you can't adopt your cattle anyway :) )
4. If the processing of adopting your cattle, it would be interesting
to allow users select server roles to be installed.

H.