Refactor: example raft-kv-rocksdb reuses example/rocksstore #4282

Job	Run time
lint	1m 44s
cluster-benchmark (cluster_benchmark)	47s
examples (stable, memstore)	46s
examples (stable, rocksstore)	6m 28s
openraft-feature-test (nightly)	50s
openraft-test (stable, 0)	3m 20s
examples (stable, raft-kv-memstore)	2m 37s
openraft-test (nightly, 30)	3m 25s
openraft-feature-test (nightly, serde)	52s
examples (stable, raft-kv-memstore-grpc)	1m 59s
openraft-test (nightly, 0, single-term-leader)	3m 13s
examples (stable, raft-kv-memstore-network-v2)	54s
openraft-feature-test (nightly, single-term-leader)	50s
examples (stable, raft-kv-memstore-opendal-snapshot-data)	1m 5s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	53s
examples (stable, raft-kv-memstore-singlethreaded)	55s
openraft-test-bench (nightly)	1m 9s
examples (stable, raft-kv-rocksdb)	8m 5s
rt-monoio	44s
examples (nightly, memstore)	1m 2s
examples (nightly, rocksstore)	11m 35s
stores (stores/memstore)	55s
examples (nightly, raft-kv-memstore)	2m 19s
Build (nightly, bench,serde,bt,singlethreaded)	49s
examples (nightly, raft-kv-memstore-grpc)	1m 42s
examples (nightly, raft-kv-memstore-network-v2)	1m 12s
tests-feature-test (nightly)	2m 59s
tests-feature-test (nightly, single-term-leader)	2m 57s
examples (nightly, raft-kv-memstore-opendal-snapshot-data)	1m 30s
examples (nightly, raft-kv-memstore-singlethreaded)	1m 14s
examples (nightly, raft-kv-rocksdb)	12m 19s
	1h 21m 9s

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