Code overlap between TariAddress and EmojiId

[AaronFeickert]

There is a fair amount of duplication between TariAddress and EmojiId. Both represent a public key, but TariAddress additionally includes a network representation combined with the checksum. While the use cases are strictly different (an EmojiId need not represent a wallet address), the overlap has a bad code smell that suggests the abstractions might be a bit off.

One approach to this could be including the network byte handling in EmojiId in a generic way: when constructing an EmojiId, the caller can optionally include an extra byte to be combined with the checksum. This would allow for the existing functionality to be retained, while also supporting the requirements of TariAddress.