If we accept a MPP and we forward the payment (trampoline or swap),
we need to persist the payment accepted status, or we might wrongly
release htlcs on the next restart.
lnworker.received_mpp_htlcs used to be cleaned up in maybe_cleanup_forwarding,
which only applies to forwarded payments. However, since we now
persist this dict, we need to clean it up also in the case of
payments received by us. This part of maybe_cleanup_forwarding has
been migrated to lnworker.maybe_cleanup_mpp
This will be useful if we decide to ship lntransport as a separate
package. It is also a conceptual cleanup.
Notes:
- lntransport still requires crypto.py
- parsing node id from a bolt11 invoice is not supported.
Instead of some functions operating with hex strings,
and others using bytes, this consolidates most things to use bytes.
This mainly focuses on bitcoin.py and transaction.py,
and then adapts the API usages in other files.
Notably,
- scripts,
- pubkeys,
- signatures
should be bytes in almost all places now.
