sqldb/sqlc: add message and channe flags to channel_policies table

We need to explicitly store the entire bitfield types since we may have
channel_updates with bitfields containing bits we just dont need or
understand but we still need to store the entire bitfield so that the
reconstructed announcement remains valid.

This commit only adds the new columns but does not use them yet. NOTE:
this is ok since the migration adding this schema is not available in
the production build yet.

sqldb/sqlc/models.go

@@ -69,6 +69,8 @@ type ChannelPolicy struct {
 	Disabled                sql.NullBool
 	InboundBaseFeeMsat      sql.NullInt64
 	InboundFeeRateMilliMsat sql.NullInt64
+	MessageFlags            sql.NullInt16
+	ChannelFlags            sql.NullInt16
 	Signature               []byte
 }