* api: rename AttestationVersionRepo to Client
* api: move client into separate subpkg for
clearer import paths.
* api: rename configapi -> attestationconfig
* api: rename versionsapi -> versions
* api: rename sut to client
* api: split versionsapi client and make it public
* api: split versionapi fetcher and make it public
* config: move attestationversion type to config
* api: fix attestationconfig client test
Co-authored-by: Adrian Stobbe <stobbe.adrian@gmail.com>
