To simplify the message signing API even further, we refactor the
lnwallet.MessageSigner interface to use a key locator instead of the
public key to identify which key should be signed with.
To make it possible to use a remote lnrpc server as a signer for our
wallet, we need to change our main interface to sign the message instead
of the message's digest. Otherwise we'd need to alter the
lnrpc.SignMessage RPC to accept a digest instead of only the message
which has security implications.
Add boolean parameter for test functions without changing any
existing functionality. All current tests set manual = false, but
Future tests can set manual = true to test manual requests to
update channel state.
Add a new boolean parameter without changing any existing
functionality. The parameter will be used to indicate
whether a request to update a channel's status was made
manually by a user (currently always false).
