The AuthHash is a normalized schema returned by
all OmniAuth strategies. It maps as much
user information as the provider is able to provide into the InfoHash (stored as the
`’info’` key).
Tells you if this is considered to be a valid OmniAuthAuthHash.
The requirements for that are that it has a provider name, a uid, and a
valid info hash. See InfoHash#valid? for more details there.