* remove unused code
I've removed the provider-specific code under registry, and unused nil
backend, and replaced a call to helper from backend/oss (the other
callers of that func are provisioners scheduled to be deprecated).
I also removed the Dockerfile, as our build process uses a different
file.
Finally I removed the examples directory, which had outdated examples
and links. There are better, actively maintained examples available.
* command: remove various unused bits
* test wasn't running
* backend: remove unused err
Terraform Registry (and other registry implementations) can now return
an array of warnings with the versions response. These warnings are now
displayed to the user during a `terraform init`.
When verifying the signature of the SHA256SUMS file, we have been
hardcoding HashiCorp's public GPG key and using it as the keyring.
Going forward, Terraform will get a list of valid public keys for a
provider from the Terraform Registry (registry.terraform.io), and use
them as the keyring for the openpgp verification func.
James Bardin