Derives the URL to openid-configuration from url that either points at the
root URL of the provider or directly at .well-known/openid-configuration.
@example
if(url.endsWith('.well-known/openid-configuration')){ // `${url}` will be used to resolve the provider's configuration }else{ // `${url}/.well-known/openid-configuration` will be used to resolve the provider's configuration }
Derives the URL to openid-configuration from url that either points at the root URL of the provider or directly at
.well-known/openid-configuration.