Handle a few common macOS errors, as well as gRPC unimplemented errors, and
return more user-friendly messages in their place.
gravitational/teleport.e#514
Implement the client-side enrollment ceremony and define the interfaces for
native-only methods.
The server-side implementation for Device Trust is Enterprise-only, so sadly we
can't against the real server here. I've opted to write a couple of fakes that
we can reuse for the device authentication ceremony and, eventually, to test
against other OS implementations. The current design attempts to write as much
as possible without build tags, so we can unit test the most of it.
Follow ups will add the native parts and wire the ceremony to the corresponding
`tsh` command.
gravitational/teleport.e#514
Alan Parra