queue.Operations: add context cancelation and record error

[ecordell]

This addresses an important case where a (preexisting) handler is wrapped in another handler

Canceling the context when a queue operation is performed signals to wrappers that the handler chain should stop (and also protects against accidental further processing, i.e. with a kube client)

Recording the error on the operations context (which is similar to context.Context) gives the caller a chance to do something with the error before returning.

Example:

var Queue = queue.NewQueueOperationsCtx()

func (s *Wrapper) Handle(ctx context.Context) {
	otherHandler.Handle(ctx)
        if errors.Is(ctx.Err(), context.Canceled) {
            if err := Queue.Error(ctx); err != nil {
                logger.V(2).Error(, "error calling underlying handler")
            }
            return
        }
	s.next.Handle(ctx)
}