This commit changes mission control to partially base the estimated
probability for untried connections on historical results obtained in
previous payment attempts. This incentivizes routing nodes to keep all
of their channels in good shape.
This commit exposes the three main parameters that influence mission
control and path finding to the user as command line or config file
flags. It allows for fine-tuning for optimal results.
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.
