Normalize key input for ipns methods

[tabcat]

The ipns methods across the different packages take a number of different types for the routing key.

@helia/ipns:

• resolve - key: PublicKey | MultihashDigest<0x00 | 0x12>
• republishRecord - key: MultihashDigest<0x00 | 0x12> | string

@helia/delegated-routing-v1-http-api-client

• getIPNS - libp2pKey: CID<unknown, 0x72, 0x00 | 0x12, 1>
• putIPNS - libp2pKey: CID<unknown, 0x72, 0x00 | 0x12, 1>

It would be nice to decide on a type to handle these throughout the codebase.
I think this would reduce confusion for users.

First it would be good to better understand why these different types were chosen to be used.

Related:

• @helia/ipns methods to accept CID encoded IPNS key #801
• feat(ipns): add CID support for publish, republishRecord, and resolve #852