This moves the generated pb files to the `sdk` module. This allows third parties to make use of them if desired (e.g. in upcoming plugins) and moves away from the `gen` nomenclature in the directory, since we are going to be adding some extra interface functions to the messages.
* Update protos and gen
* Add new values to targets CLI command
* Lots more plumbing of new parameters through everything
* allow fields to be set to zero value.
* Disallow set but empty name/description strings in create/update verifiers
Co-authored-by: Jim Lambert <jlambert@hashicorp.com>
Jeff Mitchell
