OIDC: support post_logout_redirect_uri in logout

*Description*:

I dont know if this functionality exists and I just cant figure it out or if this would be a new feature - I am looking to set `post_logout_redirect_uri` in an OIDC security policy so that after the logout is called via the `logoutPath` the gateway will include the `post_logout_redirect_uri` in the URL that gets set to log out, so after the RP-Initiated Logout is completed, that URI is redirected to. This parameter does appear to get appended to the URI that is created when `logoutPath` is called. Specifically, when the browser goes to `logoutPath`, a 302 is returned that redirects to the URL defined in the OIDC provider `endSessionEndpoint`, along with `id_token_hint` and `client_id`, and an encoded URI in `post_logout_redirect_uri`, but I dont know where that is coming from or how to set it.