feat: token introspection (#83)

* introspect

* introspect and client assertion

* introspect and client assertion

* scopes

* token introspection

* introspect

* refactoring

* fixes

* clenaup

* Update example/internal/mock/storage.go

Co-authored-by: Fabi <38692350+fgerschwiler@users.noreply.github.com>

* clenaup

Co-authored-by: Fabi <38692350+fgerschwiler@users.noreply.github.com>

pkg/op/authrequest.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"strings"
+	"time"
 
 	"github.com/gorilla/mux"
 
@@ -12,6 +13,23 @@ import (
 	"github.com/caos/oidc/pkg/utils"
 )
 
+type AuthRequest interface {
+	GetID() string
+	GetACR() string
+	GetAMR() []string
+	GetAudience() []string
+	GetAuthTime() time.Time
+	GetClientID() string
+	GetCodeChallenge() *oidc.CodeChallenge
+	GetNonce() string
+	GetRedirectURI() string
+	GetResponseType() oidc.ResponseType
+	GetScopes() []string
+	GetState() string
+	GetSubject() string
+	Done() bool
+}
+
 type Authorizer interface {
 	Storage() Storage
 	Decoder() utils.Decoder