[DISCUSSION] PIP-128: Add new command STOP_PRODUCER and STOP_CONSUMER

[包子]

## Motivation

Broker send `CLOSE_PRODUCER/CLOSE_CONSUMER` to client when delete topic, But 
client will be reconnect. If config `allowAutoTopicCreation=true` will trigger 
create topic again.

https://github.com/apache/pulsar/blob/9f599c9572e5d9b1f15efa6e895e7eb29b284e57/pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConnectionHandler.java#L130-L133

## Goal

Add new commands `STOP_PRODUCER/STOP_CONSUMER`, When the client receives the 
command, it only closes without reconnecting.

## API Changes

1. Add command to `BaseCommand`
```java
message BaseCommand {
    enum Type {
    // ...
    STOP_PRODUCER = 64;
    STOP_CONSUMER = 65
    }
}
```