Event Publisher enables event integration between Keycloak and OpenFGA

A Keycloak extension implements an Event Listener Provider that detects identity events (user role assignments, role-to-role assignments, etc.) and publishes them as OpenFGA tuple keys via the OpenFGA Java SDK over HTTP. This enables direct, real-time synchronization between Keycloak's identity/role model and OpenFGA's fine-grained authorization (ReBAC) system, allowing applications to use OpenFGA as a Policy Decision Point.