[refactor][java] Unify the acknowledge process for batch and non-batch message IDs

[BewareMyPower]

Motivation

When I read the acknowledge related code, I found much repeat code and
the inconsistent code style. Generally we should handle the following
cases for a given message ID:

1. The message ID doesn't contain a valid batch index, i.e. messageId instanceof BatchMessageIdImpl returns false.
2. Otherwise, it's a BatchMessageIdImpl. The behavior is determined by
   whether the batch index ACK is enabled.

For individual ACKs, the stats and unacked message tracker must be
updated according to the type of message ID. Since MessageIdImpl is
used as the key, for a BatchMessageIdImpl, we must create a
MessageIdImpl from it as the key of these hash maps.

The existing methods modifyBatchMessageIdAndStatesInConsumer and
modifyMessageIdStatesInConsumer are confused. So I decide to make the
code simple and clear.

Modifications

• Add a toMessageIdImpl method to BatchMessageIdImpl to create a
  MessageIdImpl object from it.
• Add an addAcknowledgement overload to accept an extra
  BatchMessageIdImpl argument, which is used to compute the number of
  ACK commands sent and perform batch related ACKs. The MessageIdImpl
  argument is used to update the DLQ and unacked tracker.
• Add a addIndividualAcknowledgement method for individual ACKs. This
  method accept two functions to handle ACK for batch and non-batch
  message IDs because when a list of message IDs are acknowledeged,
  doIndividualAckAsync and doIndividualBatchAck will be called
  instead of doIndividualAck and doIndividualBatchAck.

The previous modify...InConsumer methods will be merged into the
following case in addIndividualAcknowledgement:

if (batchMessageId == null || batchMessageId.ackIndividual())

Verifying this change

Rename ConsumerAckResponseTest to ConsumerAckTest. Then add some tests to verify the following states will be modified as expected.

• The interceptor's onAcknowledge and onAcknowledgeCumulative methods.
• The UnAckedMessageTracker instance in the consumer.
• The numAcksSent consumer stats.

In three cases:

• acknowledge a single message ID
• acknowledge a list of message IDs
• acknowledgeCumulative a single message ID

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Matching PR in forked repository

PR in forked repository: BewareMyPower#4

new code updated

[lhotari]

/pulsarbot rerun-failure-checks

[BewareMyPower]

@eolivelli @shoothzj Could you take a second look?