This new resource is an alternative to consul_keys that manages all keys
under a given prefix, rather than arbitrary single keys across the entire
store.
The key advantage of this resource over consul_keys is that it is able to
detect and delete keys that are added outside of Terraform, whereas
consul_keys is only able to detect changes to keys it is explicitly
managing.
This deals with some of the quirks of interacting with the Consul API,
with the goal of making the consul_keys resource implementation, and
later the consul_keys data source, less noisy to read.
Martin Atkins