Migrate `pallet-whitelist` to umbrella crate #6654

Job	Run time
preflight / preflight	1m 18s
preflight / ci-versions	1m 28s
cargo-check-benches (master)	21m 2s
cargo-check-benches (current)	24m 40s
test-frame-ui	46m 28s
cargo-check-each-crate (1)	23m 1s
cargo-check-all-crate-macos	11m 27s
cargo-check-each-crate (2)	21m 9s
test-full-crypto-feature	3m 2s
cargo-check-each-crate (3)	9m 4s
test-node-metrics	11m 4s
cargo-check-each-crate (4)	21m 12s
cargo-check-each-crate (5)	29m 58s
cargo-check-each-crate (6)	15m 5s
cargo-check-each-crate (7)	31m 7s
test-frame-examples-compile-to-wasm	3m 12s
test-deterministic-wasm	8m 1s
check-tracing	2m 24s
check-metadata-hash	7m 3s
node-bench-regression-guard	13s
All test misc tests passed	1s
	4h 51m 59s

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