Authorize URL is computed from baseURL use /.well-known/oauth-authorization-server

When login is performed, an authenticator needs to compute an authorize URL to send the request. The library is using the cluster base URL but this does not work for OCP4 as the host name needs to be different.
In order to be compliant, we should use the authorization_endpoint field from the /.well-known/oauth-authorization-server endpoint and default to /oauth/authorize