NewGRPCProvider creates a new GRPCClient instance.

NewProvider constructs a Provider, which is a container type, holding a terraform provider plugin grpc client, as well as metadata about this provider instance, eg its configuration and type.

ReadProviderConfigFile reads a yaml-formatted provider config and unmarshals it into a ProviderConfig, which knows how to generate the serialized provider config that a terraform provider expects.

FakeTerraformVersion is a nice lie we tell to providers to keep them happy TODO: is there a more sane way to negotiate version compat w/ providers?.

Provider wraps grpcProvider with some additional metadata like the provider name.

ProviderConfig models the on-disk yaml config for providers.