oidc: remote provider JWAValuesSupported struct
oidc: remote provider JWAValuesSupported struct

Extra struct is very clunky when composing proivder configs since
id_token_signing_alg_values_supported is a required fields.

coreos/go-oidc,alberts/go-oidc,alberts/go-oidc,coreos/go-oidc