SaltedSipHasher is a generic hasher that can be used with most things we
would hash in an unordered container.
Replace KeyIDHasher with SaltedSipHasher and remove now unused KeyIDHasher
This concludes backport of [[https://github.com/bitcoin/bitcoin/pull/19935 | core#19935]]
https://github.com/bitcoin/bitcoin/pull/19935/commits/95e61c1cf2a91d041c8025306ba36f0ea2806894
https://github.com/bitcoin/bitcoin/pull/19935/commits/281fd1a4a032cded7f9ea9857e3e99fc793c714b
Depends on D12149