Token Mediation / BFF Pattern Authentication Patter Redirect

[safaci2000]

Is your feature request related to a problem? Please describe.
Is Token Mediation pattern supported by gocloak? I've looked over the docs but honestly couldn't find a way of doing it.

https://datatracker.ietf.org/doc/html/draft-ietf-oauth-browser-based-apps#name-token-mediating-backend

Describe the solution you'd like
The ability to redirect a user to keycloak for authentication.

Additional context

                       +-------------+  +--------------+ +--------------+
                            |             |  |              | |              |
                            |Authorization|  |    Token     | |   Resource   |
                            |  Endpoint   |  |   Endpoint   | |    Server    |
                            |             |  |              | |              |
                            +-------------+  +--------------+ +--------------+

                                ^                        ^              ^
                                |                     (F)|           (K)|
                                |                        v              v

                                |         +-----------------------------------+
                                |         |                                   |
                                |         |    Backend for Frontend  (BFF)    |
                             (D)|         |                                   |
                                |         +-----------------------------------+
                                |
                                |           ^     ^     ^     +       ^  +
                                |      (B,I)|  (C)|  (E)|  (G)|    (J)|  |(L)
                                v           v     v     +     v       +  v

+-----------------+         +-------------------------------------------------+
|                 |  (A,H)  |                                                 |
| Static Web Host | +-----> |                    Browser                      |
|                 |         |                                                 |
+-----------------+         +-------------------------------------------------+

When no active session is found, the JavaScript application calls out to the BFF (C) to initiate the Authorization Code flow with the PKCE extension (described in Section 6.1.3.1), to which the BFF responds by redirecting the browser to the authorization endpoint (D). When the user is redirected back, the browser delivers the authorization code to the BFF (E), where the BFF can then exchange it for tokens at the token endpoint (F) using its client secret and PKCE code verifier.