To itest our autolooper, we need to be able to trigger dispatch on
demand. This functionality is included in a separate rpc server behind
a dev flag. Since it is unlikely that we need to split loop into
multiple rpc servers, this commit simply adds an additional debug server
rather than opting for a full subserver setup.
To make sure we can use the latest version of loop in LiT, we need to
make sure loop compiles against the actual v0.11.1 branch of lnd. There
were some conflicting changes to the macaroon service that didn't make
it to the branch that we need to roll back. Those changes don't affect
loop at all as we were always using the default root key ID anyway.
