Implement spending of entire UTxOs using build command with no change outputs

[Jimbo4350]

Resolves #3041

[dcoutts]

Does this actually work? Doesn't the balance check already fail if we have a balance that is less than the min utxo (which of course includes zero).

Note also that even if this passes the balance check, it does not involve paying any less in fees for the case where the change comes out to be zero. We're still calculating the fees assuming we'll have a change output. That's a much harder one to solve (and why I didn't bother in the first place).

[Jimbo4350]

Does this actually work?

I forgot to push a local change that modifies balanceCheck so this works now. I'm not going to bother to go through the hassle of reducing the fee calculation because I agree it's not worth it.

[dcoutts]

LGTM, though as suggested below I think it's worth explaining properly in the code comments.

[Jimbo4350]

bors r+

[iohk-bors]

Build succeeded:

• buildkite/cardano-node
• ci/hydra-build:required