Add detached signatures to gb archive
This will include adding a signer option to release.json and a --sign flag to gb-archive that can invoke gpg to create a detached signature for the tarball it creates.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This will include adding a signer option to release.json and a --sign flag to gb-archive that can invoke gpg to create a detached signature for the tarball it creates.