Use fundrawtransaction more in the suggested ANT workflow

[domob1812]

Upstream bitcoin/bitcoin#17211 solved a long-standing issue for doing atomic trades with names (namely that the buyer's wallet was not able to directly fund a transaction with the non-wallet name input in it).

Based on this, we can now streamline name_ant_workflow.py to make use of this new feature. This allows us to properly use fundrawtransaction to fund the final transaction including already the name input and output, and thus with correct fee estimation done. (Previously we just funded a dummy transaction with a guessed higher fee, and then added in the name input and output manually, hoping the fee would still be fine.)

[domob1812]

@JeremyRand What do you think about this, is this how we want to "suggest" ANTs to be done? The main drawback I see here is that the solver in fundrawtransaction requires the pubkey of the payment address, rather than just the address - so this is a bit more information that the seller needs to pass to the buyer (address and pubkey).

Overall, though, this seems like a clear improvement (and in fact the Bitcoin PR merged fixes an issue I believe we discussed and brought up a long time ago in this context already).

[yanmaani]

There's an RPC method in the pipeline for this which will make the manual method obsolete anyway. I will send in a PR once bitcoin/bitcoin#23201 is merged. That said, I don't imagine this code will be going away any time soon, so it seems reasonable enough to keep it updated.

Concept ACK b59aa1c.

[domob1812]

There's an RPC method in the pipeline for this which will make the manual method obsolete anyway. I will send in a PR once bitcoin/bitcoin#23201 is merged. That said, I don't imagine this code will be going away any time soon, so it seems reasonable enough to keep it updated.

Concept ACK b59aa1c.

Thanks for the review and the pointer to the other upstream PR, this will indeed be useful as well.

I still think that even if there is an RPC implementing the flow, it is good for us to have this test, both to ensure that the workflow actually works (although any regtest for the new RPC method will test this as well of course), and also more as a kind of documentation for how it works - perhaps for certain specific applications the high-level RPC method will not be suitable directly, and then users will have to fall back to a manual process.