After we moved the ChannelMonitor creation later during Channel
init, we never went back and cleaned up ChannelMonitor to remove
a number of now-useless Option<>s, so we do that now.
Watchtower will be supported through external signer interface
where a watchtower implementation may differ from a local one
by the scope of key access and pre-signed datas.
Fix a crash where previously we weren't able to detect any accepted
HTLC if its witness-encoded cltv expiry was different from expected
ACCEPTED_HTLC_SCRIPT_WEIGHT. This should work for any cltv expiry
included between 0 and 16777216 on mainnet, testnet and regtest.
The logger which decides what to refer to an on-chain claim tx was
assuming that all inputs would have a witness. While this was fine
for the one-input case, it broke the fuzzer which was connecting a
consensus-invalid transaction. Further, in the case we have multiple
inputs, some may not have a witness, which we shouldn't crash on.
This fixes 9df0250dbb.
