Add multihash code for AES-CMAC

[vorburger]

Would it make sense to allocate a multihash code for "AES-CMAC" -128 / -192 / -256 ?

• https://developers.google.com/tink/supported-key-types#mac AES-CMAC
• https://learn.microsoft.com/en-us/uwp/api/windows.security.cryptography.core.macalgorithmnames.aescmac
• https://en.wikipedia.org/wiki/One-key_MAC
• RFC 4493 https://datatracker.ietf.org/doc/html/rfc4493 & https://www.rfc-editor.org/rfc/rfc4493.html
• https://cryptography.io/en/latest/hazmat/primitives/mac/cmac/
• https://crypto.stackexchange.com/search?q=aes-cmac
• https://github.com/megrxu/AES-CMAC

[rvagg]

Only if it actually has a use as a multicodec, otherwise it's just opening the door to a very large number of permutations of MACs, block ciphers and other pieces used by TLS that will just exist for the sake of existing in the table without finding a use.