add mroe info to RaftMetrics::replication

[drmingdrmer]

RaftMetrics::replication is a map that stores the replication state for each
node, including both followers and learners. At present, the replication state
only includes the last matching log ID on the target node.

Enhancing the replication state with additional information, such as the
Unreachable status, the occurrence rate of NetworkError, or the timestamp of
the most recent RPC, would be beneficial.

[github-actions]

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