This commit removes all code related to NP2WSH htlcs. These were
historically used when segwit adoption was very sporadic and are not
used anywhere anymore. Some historical swaps stored in the DB may be
listed with incorrect htlc adresses from here on.
In this commit we add the version 3 htlc, which is implemented with
taproot script spending the two payment paths: the claim path case, and
the timeout case.
Formatting our error was stifling any grpc error returned by the
server. Instead, we bubble up our grpc error, setting an unknown
code if the server did not specifically return an error code.
This commit extends SwapResponse and SwapStatus with np2wsh and p2wsh
htlc output addresses to support both nested and native segwit htlcs
in loop-in.
Furthermore the commit adds support for native segwith loop-in htlcs.
When the htlc is paid internally, as of this commit we'll use NP2WSH,
otherwise users are free to select whether to pay the NP2WSH or the
P2WSH htlc.