* Remove signature checks from unittests. Would need to export
signature from client/fetcher (unwanted). Can't figure out a better way.
e2e test completes in ~4sec and runs automatically.
So seems like a acceptable tradeoff.
* list object is now signed, but not verified. If we start to verify the list
we will have to adapt the e2e test to restore the previous list.
Otherwise there could be conflicts between dev and release keys.
* rename to attestationconfigapi + put client and fetcher inside pkg
* rename api/version to versionsapi and put fetcher + client inside pkg
* rename AttestationConfigAPIFetcher to Fetcher