Push UTxO creation into LedgerClient impl where it belongs

[MitchTurner]

This isn't a big surprise, but we need to introduce a better intermediary representation of the UTxO and then let the LedgerClient adapter deal with either iding them or letting the blockchain give you that info.

REgardless, it needs to be pushed out of the domain. There are a few TODOs scattered through the code that relates to this.

[MitchTurner]

This is done.