Use --queue-balance instead of --queue-num

[aroradaman]

NFQueue has an option to load-balance between multiple userland queues. Maybe we can use that or let the consumer define the number of queues as a configuration.

[aojea]

I didn't experiment with that but right now, without network policies and current config, the p99 duration for processing a packet with 8k packets per seconds is 500 microseconds

I'd like to avoid premature optimization until we have more evidence of the problem