The `log.go` file of each subserver is a copy and paste of the others.
All of them have the same typo, an extra space in a comment, and the
the definition of a function not used anywhere.
In this commit, we implement the full RouterServer as specified by the
newly added sub-service as defined in router.proto. This new sub-server
has its own macaroon state (but overlapping permissions which can be
combined with the current admin.macaroon), and gives users a simplified
interface for a gRPC service that is able to simply send payment. Much
of the error reporting atm, is a place holder, and a follow up commit
will put up the infrastructure for a proper set of errors.