[feat][doc] add configurations for broker load balancing (#661)

static/reference/next/config/README.md

@@ -32,3 +32,72 @@ You can set specific configurations through Java properties.
 | **Property**       | **Description**                                              |
 | ------------------ | ------------------------------------------------------------ |
 | pulsar.enableUring | Use `io_uring` instead of `epoll` as network IO mode. `-Dpulsar.enableUring=1` means this feature is enabled. |
+
+## Broker load balancing configurations
+
+Below is a brief summary of configurations for broker load balancing. 
+
+For detailed descriptions of each configuration, see [Broker load balancing | Configurations](pathname:///reference/#/@pulsar:version_reference@/config/reference-configuration-broker).
+
+> Note
+> Configurations with an asterisk (*) are only available in the extensible load balancer.
+
+### Broker load data
+
+- loadBalancerReportUpdateMinIntervalMillis
+- loadBalancerReportUpdateThresholdPercentage
+- loadBalancerReportUpdateMaxIntervalMinutes
+- loadBalancerBandwithInResourceWeight
+- loadBalancerBandwithOutResourceWeight
+- loadBalancerCPUResourceWeight
+- loadBalancerMemoryResourceWeight
+- loadBalancerDirectMemoryResourceWeight
+- loadBalancerHistoryResourcePercentage
+
+### TopK bundle load data
+
+- loadBalancerReportUpdateMinIntervalMillis
+- statsUpdateFrequencyInSecs
+- loadBalancerMaxNumberOfBundlesInBundleLoadReport*
+
+
+### Bundle-broker assignment
+
+- loadBalancerAverageResourceUsageDifferenceThresholdPercentage
+
+### Bundle ownership system topic (ServiceUnitStateChannel)
+
+- loadBalancerServiceUnitStateTombstoneDelayTimeInSeconds*
+
+### Bundle unloading
+
+- loadBalancerEnabled
+- loadBalancerSheddingEnabled
+- loadBalancerSheddingIntervalMinutes
+- loadBalancerSheddingGracePeriodMinutes
+- loadBalancerBrokerOverloadedThresholdPercentage
+- loadBalancerLoadSheddingStrategy. The default value is [org.apache.pulsar.broker.loadbalance.impl.ThresholdShedder](https://github.com/apache/pulsar/blob/782e91fe327efe2c9c9107d6c679c2837d43935b/conf/broker.conf#L1324). Available values are:
+  -  `org.apache.pulsar.broker.loadbalance.impl.ThresholdShedder`
+  -  `org.apache.pulsar.broker.loadbalance.impl.UniformLoadShedder`
+  -  `org.apache.pulsar.broker.loadbalance.impl.OverloadShedder`
+  -  `org.apache.pulsar.broker.loadbalance.extensions.scheduler.TransferShedder`
+- loadBalancerTransferEnabled*
+- loadBalancerBrokerLoadTargetStd*
+- loadBalancerSheddingConditionHitCountThreshold*
+- loadBalancerMaxNumberOfBrokerSheddingPerCycle*
+- loadBalanceSheddingDelayInSeconds*
+- loadBalancerBrokerLoadDataTTLInSeconds*
+
+### Bundle splitting
+
+- loadBalancerEnabled
+- loadBalancerAutoBundleSplitEnabled
+- defaultNamespaceBundleSplitAlgorithm
+- loadBalancerNamespaceBundleMaxTopics
+- loadBalancerNamespaceBundleMaxSessions
+- loadBalancerNamespaceBundleMaxMsgRate
+- loadBalancerNamespaceBundleMaxBandwidthMbytes
+- loadBalancerNamespaceMaximumBundles
+- loadBalancerSplitIntervalMinutes*
+- loadBalancerNamespaceBundleSplitConditionHitCountThreshold*
+- loadBalancerMaxNumberOfBundlesToSplitPerCycle*