Feature: Add `TypeConfigExt` to simplify `RaftTypeConfig` Access #3677

Job	Run time
cluster-benchmark (cluster_benchmark)	49s
examples (stable, memstore)	41s
external-stores (stores/rocksstore-v2)	6m 20s
examples (stable, raft-kv-memstore)	2m 34s
lint	11m 30s
examples (stable, raft-kv-memstore-generic-snapshot-data)	1m 17s
openraft-features (nightly, generic-snapshot-data)	1m 3s
examples (stable, raft-kv-memstore-opendal-snapshot-data)	1m 55s
openraft-feature-test (nightly)	54s
openraft-test (stable, 0)	3m 43s
examples (stable, raft-kv-memstore-singlethreaded)	59s
openraft-feature-test (nightly, serde)	1m 6s
openraft-test (nightly, 30)	3m 26s
examples (stable, raft-kv-rocksdb)	8m 21s
openraft-test-bench (nightly)	1m 7s
openraft-feature-test (nightly, single-term-leader)	53s
openraft-test (nightly, 0, single-term-leader)	3m 14s
examples (nightly, memstore)	1m 0s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	1m 2s
examples (nightly, raft-kv-memstore)	2m 21s
stores (memstore)	1m 7s
examples (nightly, raft-kv-memstore-generic-snapshot-data)	1m 21s
Build (nightly, bench,serde,bt,singlethreaded)	54s
stores (rocksstore)	6m 13s
tests-feature-test (nightly)	2m 58s
examples (nightly, raft-kv-memstore-opendal-snapshot-data)	1m 58s
stores (sledstore)	1m 7s
tests-feature-test (nightly, single-term-leader)	2m 58s
examples (nightly, raft-kv-memstore-singlethreaded)	1m 18s
tests-feature-test (nightly, loosen-follower-log-revert)	2m 53s
examples (nightly, raft-kv-rocksdb)	13m 37s
	1h 30m 39s

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