Inconsistency between generated invoice description (label) between CLN and others

[kristapsk]

When using CLN as a backend, invoice description is set to SatSale-uuid.

SatSale/node/clightning.py

Lines 80 to 82 in 4647840

	lnd_invoice = self.clightning.invoice(
	msats_amount, label, "SatSale-{}".format(label), expiry
	)

For bitcoind / LND, it just uses plain uuid.

SatSale/node/bitcoind.py

Lines 127 to 130 in 4647840

	if not self.tor:
	address = self.rpc.getnewaddress(label)
	else:
	address = self.call_tor_bitcoin_rpc("getnewaddress", [label])["result"]

SatSale/node/lnd.py

Lines 130 to 132 in 4647840

	res = self.lnd.add_invoice(
	value=sats_amount, memo=memo, description_hash=description_hash, expiry=expiry
	)

I think we should make it consistent. Having that "SatSale-" prefix is IMO cool if we make it configurable. So that user will see in his wallet payment history something like MyCoolStore-uuid and he will immediately understand to whom he made the payment. Thoughts?