Package router routes HTTP requests to corresponding handler.
The authenticate request is defined as path "/authn" and only accept HTTP POST request.
The authorization request is defined as path "/authz" and only accept HTTP POST request.
NewRoutes returns routes defined for handling authenticate and authorize requests.
The authenticate requests will accept for only HTTP POST requests, and the endpoint is /authn.
The authorize requests will accept for only HTTP POST requests, and the endpoint is /authz.