[improve][client] Add independent multiTopicsSinglePartitionReceiverQueueSize config for single partition consumer in multi-topics consumer to reduce memory consumption

[oneby-wang]

Motivation

There no independent receiverQueueSize config for single partition consumer in MultiTopicsConsumerImpl and PatternMultiTopicsConsumerImpl. Although maxTotalReceiverQueueSizeAcrossPartitions config can limit in-memory messages of a single topic with multi-partitions, but it can't limit in-memory messages of multi-topics.

For example, if we subscribe to a regex pattern that matches 1000 non-partitioned topics. Before this PR, each non-partitioned topic consumer's receiverQueueSize is 1000(ConsumerImpl uses the same receiverQueueSize value as PatternMultiTopicsConsumerImpl), the max messages in memory is 1000 + 1000 * 1000 = 1001000. Let's ignore the insignificant number 1000, if each message size is 8Kb, then we need 1000000 * 8Kb = 7,812.5MB memory to boot our application in catch-up read situation, which is unnecessary.

https://github.com/apache/pulsar/blob/e6560657e20d30103f2f01c3a24600dad1ba9ab6/pulsar-client/src/main/java/org/apache/pulsar/client/impl/MultiTopicsConsumerImpl.java#L236-L249

For backward compatibility, add multiTopicsSinglePartitionReceiverQueueSizeEnable switch, the default value is set to false.

Modifications

Add independent multiTopicsSinglePartitionReceiverQueueSize config for single consumer in MultiTopicsConsumerImpl to reduce memory consumption.

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