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: https://github.com/lightninglabs/faraday/blob/b12a8584070efeb67ce96a98a33de4c802c4ba76/accounting/config.go#L194-L198