Tasks are automatically granted access to variables on a path that matches their
workload identity, with a well-known prefix. Change the prefix to `nomad/jobs`
to allow for future prefixes like `nomad/volumes` or `nomad/plugins`. Reserve
the prefix by emitting errors during validation.
* SV: CAS
* Implement Check and Set for Delete and Upsert
* Reading the conflict from the state store
* Update endpoint for new error text
* Updated HTTP api tests
* Conflicts to the HTTP api
* SV: structs: Update SV time to UnixNanos
* update mock to UnixNano; refactor
* SV: encrypter: quote KeyID in error
* SV: mock: add mock for namespace w/ SV
This PR splits SecureVariable into SecureVariableDecrypted and
SecureVariableEncrypted in order to use the type system to help
verify that cleartext secret material is not committed to file.
* Make Encrypt function return KeyID
* Split SecureVariable
Co-authored-by: Tim Gross <tgross@hashicorp.com>
