jimmy wu

Results 2 issues of jimmy wu

for #277 - update OidcProvider to use SignedJWT - update the `/token` endpoint to use SignedJWT with RS256 instead of PlainJWT to comply with oidc spec - create the `/certs`...

TCK

hello, i'm proposing to change the `userinfoEndpoint` in `OpenIdProviderMetadata` from `Required` to `Optional` in its javadoc. i think this will make it more aligned with the authentication mechanism spec since:...