An OpenID Connect configuration. Snake_case keys, as a discovery document delivers them, are accepted and normalized.
The scopes to request.
The Google OAuth client secret. Its keys stay
snake_case, because it is an on-disk wire format. A {web: {…}} or
{installed: {…}} wrapper is unwrapped.
A [scheme, credential] pair.
Builds an OpenID Connect scheme and credential from a configuration object and a client-secret object.