Migrate `pallet-authority-discovery` to umbrella crate #10767

Job	Run time
preflight / preflight	41s
preflight / ci-versions	1m 5s
build (polkadot-availability-recovery, availability-recovery-regression-bench)	15m 6s
build (polkadot-availability-distribution, availability-distribution-regression-bench)	12m 43s
build (polkadot-node-core-approval-voting, approval-voting-regression-bench)	30m 18s
build (polkadot-statement-distribution, statement-distribution-regression-bench)	11m 46s
publish-benchmarks	0s
	1h 11m 39s

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