Add MakerToTakerMessagefor Invalid Swap Amounts

[KnowWhoami]

coinswap/src/maker/handlers.rs

Lines 244 to 257 in 67c39a9

	if total_funding_amount >= self.config.min_size
	&& total_funding_amount < self.wallet.read()?.store.offer_maxsize
	{
	log::info!(
	"[{}] Total Funding Amount = {} | Funding Txids = {:?}",
	self.config.port,
	Amount::from_sat(total_funding_amount),
	funding_txids
	);
	Ok(MakerToTakerMessage::RespContractSigsForSender(
	ContractSigsForSender { sigs },
	))
	} else {
	Err(MakerError::General("not enough funds"))

Whenever Maker gets ReqContractSigsForSender message from Taker and the send amount is not within the range of maker i.e (min_swap_amount, max_offersize) -> then we propagate the error which ultimately reaches to handle_client as shown:

coinswap/src/maker/server.rs

Lines 544 to 545 in 67c39a9

	if let Err(e) = handle_client(maker_for_handler, &mut stream, client_addr) {
	log::error!("[{}] Error Handling client request {:?}", port, e);

which causes failure to handle client and maker recieves the log message that it fails to handle the client.
Though this wouldn't cause any damage to Maker but it is bad in terms of UX because It's the fault of Taker not Maker.

Proposed Solution:

• Create a new MakerToTakerMessage variant which states about this situation that the send amount is not within the range of that Maker.