This commit modifies the existing FindRoute method on the ChannelRouter
to now use the KSP implementation added in a prior commit.
This new method FindRoutes, is able to find all the possible paths
between a source and destination. The method takes all paths reported
by findPaths, and attempt to turn each of them into a route. A route
differs from a path in that is has complete time-lock and fee
information. Some paths may not be able to be turned into routes as
once fees are accounted for the have an insufficient flow. We then take
the routes, sort them by total fee (with time-lock being a
time-breaker), then return them in sorted order.
This commit modifies the `ChannelEdgeUpdate` struct to include the
channel point itself within the notifications. Such a change improves
the notificaiton experience for callers as it allows them to filter out
update notifications based on a familiar object within the codebase: a
channel point.
