Part of: ipfs/kubo#6815

We are deprecating these functions as ipfs strives to store
multihashes directly on the datastore, rather than CIDs.

Thus multiple CIDs might map to the same multihash. Making this functions
reflect that behaviour might cause silent breakage in users. We prefer loud
breakage.

Users using CidToDsKey(c) should move to MultihashToDsKey(c.Hash()).

Users using DsKeyToCid() should move to DsKeyToCidV1Raw() or DsKeyToMultihash().

Note that datastore should handle migrations to replace existing CID-encoded
keys with raw multihashes, or preserve DsKeyToCid() and CidToDsKey() in their
own codebases.

Allow passing in whatever codec type the user wants