[feat][broker] Support configuring replicator rate limiter per cluster

[nodece]

Motivation

This PR enhances Pulsar's replication capabilities by adding support for configuring replicator rate limiters on a per-cluster basis. Currently, Pulsar only supports a single global replicator dispatch rate that applies to all remote clusters. This limitation makes it difficult to optimize replication performance when different destination clusters have varying network conditions or resource constraints.

By allowing administrators to configure different dispatch rates for different destination clusters, this PR enables more granular control over replication traffic, which can help prevent network congestion and improve overall system stability.

Modifications

• Added support for configuring replicator dispatch rates on a per-cluster basis at both namespace and topic levels.
• Extended the Admin API to support cluster-specific replicator dispatch rate operations.
• Modified the internal replicator implementation to use cluster-specific rate limiters when available.
• Updated the CLI commands to support the new cluster parameter.
• Maintained backward compatibility with existing configurations.
• Added comprehensive test coverage for the new functionality.

Documentation

• doc
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• doc-complete