Add support for creating, updating, and deleting projects, as well as
their enabled services and their IAM policies.
Various concessions were made for backwards compatibility, and will be
removed in 0.9 or 0.10.
This change doesn't make much sense now, as projects are read-only
anyways, so there's not a lot that importing really does for you--you
can already reference pre-existing projects just by defining them in
your config.
But as we discussed #10425, this change made more and more sense. In a
world where projects can be created, we can no longer reference
pre-existing projects just by defining them in config. We get that
ability back by making projects importable.
