Feature: add absolute timestamp `RaftMetrics::last_quorum_acked` #3077

Job	Run time
openraft-test-bench (nightly)	59s
stores (stores/memstore)	57s
stores (stores/rocksstore)	6m 17s
cluster-benchmark (cluster_benchmark)	47s
examples (stable, memstore)	35s
stores (stores/sledstore)	1m 1s
lint	6m 9s
examples (stable, raft-kv-memstore)	2m 32s
openraft-feature-test (nightly)	49s
examples (stable, raft-kv-memstore-network-v2)	53s
openraft-test (stable, 0)	3m 18s
examples (stable, raft-kv-memstore-opendal-snapshot-data)	1m 40s
Build (nightly, bench,serde,bt,singlethreaded)	52s
openraft-feature-test (nightly, serde)	51s
openraft-test (nightly, 30)	3m 39s
examples (stable, raft-kv-memstore-singlethreaded)	1m 7s
openraft-feature-test (nightly, single-term-leader)	51s
openraft-test (nightly, 0, single-term-leader)	3m 20s
examples (stable, raft-kv-rocksdb)	8m 24s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	49s
tests-feature-test (nightly)	3m 4s
examples (nightly, memstore)	52s
examples (nightly, raft-kv-memstore)	2m 14s
examples (nightly, raft-kv-memstore-network-v2)	1m 19s
tests-feature-test (nightly, single-term-leader)	2m 56s
examples (nightly, raft-kv-memstore-opendal-snapshot-data)	1m 49s
tests-feature-test (nightly, loosen-follower-log-revert)	2m 55s
examples (nightly, raft-kv-memstore-singlethreaded)	1m 28s
examples (nightly, raft-kv-rocksdb)	12m 20s
	1h 14m 47s

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