Export of cl/270900150.
To refer to a KMS key or key ring, we should use the stable `.self_link`. Using `.id` instead provides an unstable identifier which may change (and it will change in the upcoming update of the google provider to 2.9.1). A change in the identifier will cause Terraform to destroy and recreate the key. Destroying the key means all data associated with it is lost; the key cannot be recreated.
This CL replaces `.id` with `.self_link`, so all of those problems will not happen. In addition, `prevent_destroy` protects the key against delete-and-recreate in general.
* Move terraform and kubernetes folder to be under proxy
There is no reason for them to be under proxy/src/... any more now that
we have a Gradle-idiomatic folder structure.
