Expose a full nixosConfiguration?

[chreekat]

Like I just mentioned in #9, I don't have a firm decision on how to publish items from this repo.

Originally, my idea was to build as full of a nixosConfiguration as possible. Then, the private deploy repo would just add secrets.

Later, I wrote this:

    # FIXME: Rather than define the whole system as a module here, just expose
    # the services as modules.
    #
    # My old strategy was to try to define *everything* in this repo, so that
    # the private deployment repo would be a very thin shim that adds secrets.
    # But that proved too inflexible. My new strategy is to just define the
    # services here, and put the whole systems together in the deployment repo.
    # This has already been done for stackage, but still needs to be done for
    # hf-cert-1.

The problem with this new plan is that writing tests in this repo gets harder. I end up needing to define a nixosConfiguration anyway, don't I? Hmmmm