Support adding key sets via OpenID connect discovery

[kevmoo]

See https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfig

So instead of adding https://www.googleapis.com/oauth2/v3/certs

I should be able to add https://accounts.google.com/.well-known/openid-configuration which references the above via the jwks_uri entry

[rbellens]

Hi @kevmoo ,

This package only implements the jose specs. For openid related stuff, there are other packages, like openid_client. Why do you think this should be part of this package?

[kevmoo]

There's overlap here, right? We want logic to cache the certs response, this is just one step up the chain.