feat: Token Revocation, Request Object and OP Certification (#130)

FEATURES (and FIXES):
- support OAuth 2.0 Token Revocation [RFC 7009](https://datatracker.ietf.org/doc/html/rfc7009)
- handle request object using `request` parameter [OIDC Core 1.0 Request Object](https://openid.net/specs/openid-connect-core-1_0.html#RequestObject)
- handle response mode
- added some information to the discovery endpoint:
  - revocation_endpoint (added with token revocation) 
  - revocation_endpoint_auth_methods_supported (added with token revocation)
  - revocation_endpoint_auth_signing_alg_values_supported (added with token revocation)
  - token_endpoint_auth_signing_alg_values_supported (was missing)
  - introspection_endpoint_auth_signing_alg_values_supported (was missing)
  - request_object_signing_alg_values_supported (added with request object)
  - request_parameter_supported (added with request object)
 - fixed `removeUserinfoScopes ` now returns the scopes without "userinfo" scopes (profile, email, phone, addedd) [source diff](https://github.com/caos/oidc/pull/130/files#diff-fad50c8c0f065d4dbc49d6c6a38f09c992c8f5d651a479ba00e31b500543559eL170-R171)
- improved error handling (pkg/oidc/error.go) and fixed some wrong OAuth errors (e.g. `invalid_grant` instead of `invalid_request`)
- improved MarshalJSON and added MarshalJSONWithStatus
- removed deprecated PEM decryption from `BytesToPrivateKey`  [source diff](https://github.com/caos/oidc/pull/130/files#diff-fe246e428e399ccff599627c71764de51387b60b4df84c67de3febd0954e859bL11-L19)
- NewAccessTokenVerifier now uses correct (internal) `accessTokenVerifier` [source diff](https://github.com/caos/oidc/pull/130/files#diff-3a01c7500ead8f35448456ef231c7c22f8d291710936cac91de5edeef52ffc72L52-R52)

BREAKING CHANGE:
- move functions from `utils` package into separate packages
- added various methods to the (OP) `Configuration` interface [source diff](https://github.com/caos/oidc/pull/130/files#diff-2538e0dfc772fdc37f057aecd6fcc2943f516c24e8be794cce0e368a26d20a82R19-R32)
- added revocationEndpoint to `WithCustomEndpoints ` [source diff](https://github.com/caos/oidc/pull/130/files#diff-19ae13a743eb7cebbb96492798b1bec556673eb6236b1387e38d722900bae1c3L355-R391)
- remove unnecessary context parameter from JWTProfileExchange [source diff](https://github.com/caos/oidc/pull/130/files#diff-4ed8f6affa4a9631fa8a034b3d5752fbb6a819107141aae00029014e950f7b4cL14)

pkg/http/cookie.go

@@ -0,0 +1,110 @@
+package http
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gorilla/securecookie"
+)
+
+type CookieHandler struct {
+	securecookie *securecookie.SecureCookie
+	secureOnly   bool
+	sameSite     http.SameSite
+	maxAge       int
+	domain       string
+}
+
+func NewCookieHandler(hashKey, encryptKey []byte, opts ...CookieHandlerOpt) *CookieHandler {
+	c := &CookieHandler{
+		securecookie: securecookie.New(hashKey, encryptKey),
+		secureOnly:   true,
+		sameSite:     http.SameSiteLaxMode,
+	}
+
+	for _, opt := range opts {
+		opt(c)
+	}
+	return c
+}
+
+type CookieHandlerOpt func(*CookieHandler)
+
+func WithUnsecure() CookieHandlerOpt {
+	return func(c *CookieHandler) {
+		c.secureOnly = false
+	}
+}
+
+func WithSameSite(sameSite http.SameSite) CookieHandlerOpt {
+	return func(c *CookieHandler) {
+		c.sameSite = sameSite
+	}
+}
+
+func WithMaxAge(maxAge int) CookieHandlerOpt {
+	return func(c *CookieHandler) {
+		c.maxAge = maxAge
+		c.securecookie.MaxAge(maxAge)
+	}
+}
+
+func WithDomain(domain string) CookieHandlerOpt {
+	return func(c *CookieHandler) {
+		c.domain = domain
+	}
+}
+
+func (c *CookieHandler) CheckCookie(r *http.Request, name string) (string, error) {
+	cookie, err := r.Cookie(name)
+	if err != nil {
+		return "", err
+	}
+	var value string
+	if err := c.securecookie.Decode(name, cookie.Value, &value); err != nil {
+		return "", err
+	}
+	return value, nil
+}
+
+func (c *CookieHandler) CheckQueryCookie(r *http.Request, name string) (string, error) {
+	value, err := c.CheckCookie(r, name)
+	if err != nil {
+		return "", err
+	}
+	if value != r.FormValue(name) {
+		return "", errors.New(name + " does not compare")
+	}
+	return value, nil
+}
+
+func (c *CookieHandler) SetCookie(w http.ResponseWriter, name, value string) error {
+	encoded, err := c.securecookie.Encode(name, value)
+	if err != nil {
+		return err
+	}
+	http.SetCookie(w, &http.Cookie{
+		Name:     name,
+		Value:    encoded,
+		Domain:   c.domain,
+		Path:     "/",
+		MaxAge:   c.maxAge,
+		HttpOnly: true,
+		Secure:   c.secureOnly,
+		SameSite: c.sameSite,
+	})
+	return nil
+}
+
+func (c *CookieHandler) DeleteCookie(w http.ResponseWriter, name string) {
+	http.SetCookie(w, &http.Cookie{
+		Name:     name,
+		Value:    "",
+		Domain:   c.domain,
+		Path:     "/",
+		MaxAge:   -1,
+		HttpOnly: true,
+		Secure:   c.secureOnly,
+		SameSite: c.sameSite,
+	})
+}