[fix][cpp] Support retry and apply operation timeout for lookup requests

[BewareMyPower]

Motivation

Currently the operation timeout only works for requests other than
lookup, like SEND and FLOW. However, the lookup requests, which are sent
by LookupService, should also apply the operation timeout, see

pulsar/pulsar-client/src/main/java/org/apache/pulsar/client/impl/PulsarClientImpl.java

Lines 1019 to 1025 in 7075a5c

	AtomicLong opTimeoutMs = new AtomicLong(conf.getLookupTimeoutMs());
	Backoff backoff = new BackoffBuilder()
	.setInitialTime(conf.getInitialBackoffIntervalNanos(), TimeUnit.NANOSECONDS)
	.setMandatoryStop(opTimeoutMs.get() * 2, TimeUnit.MILLISECONDS)
	.setMax(conf.getMaxBackoffIntervalNanos(), TimeUnit.NANOSECONDS)
	.create();
	getPartitionedTopicMetadata(topicName, backoff, opTimeoutMs,

In addition, no attempts would be retried if lookup failed even due to a
retryable reason. For example, if some of all configured brokers were
down, the C++ client would fail immediately.

Therefore, this PR intends to retry lookup for some certain cases:

• The connection cannot be established, except connection timeout, which
  is controlled by the connection timeout.
• A ServiceNotReady error is received, except it's caused by
  PulsarServerException, e.g. the listener name is wrong.

Then, apply the operation timeout to avoid infinite retries.

Modifications

• Add a ResultRetryable error code, which should only be used
  internally. Complete the futures with this error in the cases said
  previously.
• Add a RetryableLookupService implementation to support retries based
  on the backoff policy. Replace the directly usages of LookupService
  implementations with this class in ClientImpl.

The following tests are added:

• ClientTest.testMultiBrokerUrl: verify when multiple brokers are
  configured, even if one of them is not available, the creation of
  producer or consumer could still succeed.
• LookupService.testRetry: verify all lookup methods could be retried.
• LookupService.testTimeout: verify all lookup methods could be
  completed with ResultTimeout if no brokers are available.

TODO

In future, we should add lookup timeout instead of operation timeout for
lookup requests and separate lookup connection pool, see PIP-91.

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