refactor: move graph related DB code to graph/db from channeldb

This is a pure refactor commit. It moves over all the graph related CRUD
code from `channeldb` to `graph/db`.

log.go

@@ -21,6 +21,7 @@ import (
 	"github.com/lightningnetwork/lnd/discovery"
 	"github.com/lightningnetwork/lnd/funding"
 	"github.com/lightningnetwork/lnd/graph"
+	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/healthcheck"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/invoices"
@@ -194,6 +195,7 @@ func SetupLoggers(root *build.SubLoggerManager, interceptor signal.Interceptor)
 	AddSubLogger(
 		root, blindedpath.Subsystem, interceptor, blindedpath.UseLogger,
 	)
+	AddV1SubLogger(root, graphdb.Subsystem, interceptor, graphdb.UseLogger)
 }
 
 // AddSubLogger is a helper method to conveniently create and register the