feat: add setup method for privilege event consumers

Adds a Setup method to PrivilegeHandler that configures AMQP consumers 
for user and privilege events. This enables the handling of User.Added, 
User.Removed, Privilege.Added, and Privilege.Removed events in a 
streamlined manner, enhancing the event-driven capabilities of the 
handler.

client.go

@@ -75,6 +75,15 @@ func (h *PrivilegeHandler) Fetch() error {
 	return nil
 }
 
+func (h *PrivilegeHandler) Setup() []goamqp.Setup {
+	return []goamqp.Setup{
+		goamqp.TransientEventStreamConsumer("User.Added", h.Process, UserAdded{}),
+		goamqp.TransientEventStreamConsumer("User.Removed", h.Process, UserRemoved{}),
+		goamqp.TransientEventStreamConsumer("Privilege.Added", h.Process, PrivilegeAdded{}),
+		goamqp.TransientEventStreamConsumer("Privilege.Removed", h.Process, PrivilegeRemoved{}),
+	}
+}
+
 // Process privilege-related events and update the internal state
 func (h *PrivilegeHandler) Process(msg interface{}, _ goamqp.Headers) (interface{}, error) {
 	switch ev := msg.(type) {