Properly advance state when swap is manually refunded

[binarybaron]

Describe the bug
When manually refunding a swap, the state that is saved in the database is not advanced properly.

 ./swap --testnet refund --swap-id 417e8829-bc15-4f03-b7d8-482cb6583356 
Published Bitcoin transaction txid=4dfb63a139d5f00d31b55beeabcf229647f18d6f68c44e09d7750ee185a6b1f2 kind=refund
Waiting for Bitcoin transaction finality txid=4dfb63a139d5f00d31b55beeabcf229647f18d6f68c44e09d7750ee185a6b1f2 required_confirmation=2
Waiting for Bitcoin transaction finality txid=4dfb63a139d5f00d31b55beeabcf229647f18d6f68c44e09d7750ee185a6b1f2 seen_confirmations=1 needed_confirmations=2

./swap --testnet history
+--------------------------------------+------------------+
| SWAP ID                              | STATE            |
+=========================================================+
| 417e8829-bc15-4f03-b7d8-482cb6583356 | btc is cancelled |
+--------------------------------------+------------------+

Lost/trapped Funds
No

Platform (please complete the following information):

• CLI (probably also ASB)
• Software Version 0.10.2
• Operating System: Ubuntu

[binarybaron]

xmr-btc-swap/swap/src/protocol/bob/state.rs

Lines 660 to 666 in 3ce4dff

	pub async fn publish_refund_btc(&self, bitcoin_wallet: &bitcoin::Wallet) -> Result<()> {
	let signed_tx_refund = self.signed_refund_transaction()?;
	let (_, subscription) = bitcoin_wallet.broadcast(signed_tx_refund, "refund").await?;
	subscription.wait_until_final().await?;
	Ok(())
	}

xmr-btc-swap/swap/src/protocol/bob/state.rs

Lines 644 to 658 in 3ce4dff

	pub async fn submit_tx_cancel(&self, bitcoin_wallet: &bitcoin::Wallet) -> Result<Txid> {
	let transaction = bitcoin::TxCancel::new(
	&self.tx_lock,
	self.cancel_timelock,
	self.A,
	self.b.public(),
	self.tx_cancel_fee,
	)
	.complete_as_bob(self.A, self.b.clone(), self.tx_cancel_sig_a.clone())
	.context("Failed to complete Bitcoin cancel transaction")?;
	let (tx_id, _) = bitcoin_wallet.broadcast(transaction, "cancel").await?;
	Ok(tx_id)
	}

It seems that you have to wait for the refund transaction to be confirmed with 2 confirmations and only then the state will be advanced to BtcRefunded. This makes sense, but doesn't seem to be consistent with the way this is handled in regards to the cancel transaction. Also, if someone manually refunds their swap and then decides not to wait 20 minutes for the cli to pick up the two confirmations, there is no way for Bob to ever properly "finish" the swap (so that the state machine is in a "Done" state). I think it would make sense to remove that 2 confirmations requirement.