feat(op): Server interface (#447)

* first draft of a new server interface

* allow any response type

* complete interface docs

* refelct the format from the proposal

* intermediate commit with some methods implemented

* implement remaining token grant type methods

* implement remaining server methods

* error handling

* rewrite auth request validation

* define handlers, routes

* input validation and concrete handlers

* check if client credential client is authenticated

* copy and modify the routes test for the legacy server

* run integration tests against both Server and Provider

* remove unuse ValidateAuthRequestV2 function

* unit tests for error handling

* cleanup tokenHandler

* move server routest test

* unit test authorize

* handle client credentials in VerifyClient

* change code exchange route test

* finish http unit tests

* review server interface docs and spelling

* add withClient unit test

* server options

* cleanup unused GrantType method

* resolve typo comments

* make endpoints pointers to enable/disable them

* jwt profile base work

* jwt: correct the test expect

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

pkg/op/config.go

@@ -20,14 +20,14 @@ var (
 type Configuration interface {
 	IssuerFromRequest(r *http.Request) string
 	Insecure() bool
-	AuthorizationEndpoint() Endpoint
-	TokenEndpoint() Endpoint
-	IntrospectionEndpoint() Endpoint
-	UserinfoEndpoint() Endpoint
-	RevocationEndpoint() Endpoint
-	EndSessionEndpoint() Endpoint
-	KeysEndpoint() Endpoint
-	DeviceAuthorizationEndpoint() Endpoint
+	AuthorizationEndpoint() *Endpoint
+	TokenEndpoint() *Endpoint
+	IntrospectionEndpoint() *Endpoint
+	UserinfoEndpoint() *Endpoint
+	RevocationEndpoint() *Endpoint
+	EndSessionEndpoint() *Endpoint
+	KeysEndpoint() *Endpoint
+	DeviceAuthorizationEndpoint() *Endpoint
 
 	AuthMethodPostSupported() bool
 	CodeMethodS256Supported() bool