[PP-1] Revoke refresh tokens

patch against 6.x

If it's helpful to others, we recently updated the Simple OAuth Revoke → module which just adds the /oauth/revoke route as outlined by the RFC 7009.

(Note: The patch in this issue also adds an /oauth/logout endpoint; that's not part of the RFC 7009 spec so it's not in the Simple OAuth Revoke module.)

To add to this long chain: here a merge request for the simple_oauth_revoke module that adds support for 6.x-dev and makes the module compatible with Drupal 11: https://www.drupal.org/project/simple_oauth_revoke/issues/3541068#commen... ✨ Support Drupal 11 and simpleoauth 6.x Active