This commit is a refactor of how we construct htlcs to make it possible
to pass in internal keys for the sender and receiver when creating P2TR
htlcs. Furthermore the commit also cleans up constructors to not pass in
script versions and output types to make the code more readable.
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.
This commit bumps the current protocol version and integrates htlc v2
with loop in/out for new swaps, while keeping htlc v1 for any pending
swaps with previous protocol versions.
