Drop need to store pending inbound payments

and replace payment_secret with encrypted metadata

See docs on `inbound_payment::verify` for details

Also add min_value checks to all create_inbound_payment* methods

Author: valentinewallace

lightning-invoice/src/utils.rs

@@ -63,7 +63,7 @@ where
 	let (payment_hash, payment_secret) = channelmanager.create_inbound_payment(
 		amt_msat,
 		DEFAULT_EXPIRY_TIME.try_into().unwrap(),
-	);
+	).unwrap();
 	let our_node_pubkey = channelmanager.get_our_node_id();
 	let mut invoice = InvoiceBuilder::new(network)
 		.description(description)