Payment requests should NOT be decoded via a network call

[torkelrogstad]

Audits of my node should be reasonably fast. It currently has about 7000 payments on it. I see that when doing audits each of the payments result in a network call to decode the payment request. This could just as well be done in-memory, which would speed things up by quite a lot.

[Roasbeef]

Makes sense.

If you're interested in tackling this issue, here's the area you need to swap out a network call for a function call into the zpay32 library:

faraday/accounting/config.go

Lines 194 to 198 in b12a858

	DecodePayReq: func(payReq string) (*lndclient.PaymentRequest,
	error) {
	return lnd.Client.DecodePaymentRequest(ctx, payReq)
	},